Dr Matt Nolan -- UAF

25 April 10, McCall Glacier

The trip hasnt gone exactly as planned, but has been pretty successful so far.

Our planned date of departure to McCall Glacier from Fairbanks was April 21. Josh Goetz from Ice Core Drilling Services (ICDS) and Andy Reese from University of Southern Mississippi (USM) were due to arrive two days earlier. That morning I got a call from Andy, saying that he was too sick to get on the plane. Apparently he had a nasty sinus infection earlier in the week, and as we learned a few days later he had an allergic reaction to the drugs he had been prescribed. There were only the three of us as the primary worker-bees on the trip, so being a man down would put a serious crimp in our productivity. Kristin and Turner were also coming, as volunteers for USM (and not paid for with UAF funds...), but their main jobs were focused around camp activities. So we were faced with the decision to play man down, delay the start of the trip until Andy recovered, or try to line up someone else on very short notice. I gave David Silverstone a call as a Hail Mary pass, and fortunately he had some time in his schedule and was able to make it.

Meanwhile, we had tried hard to get packed in advance, staying up late a few days before our departure so that the night before departure we could actually get some sleep. This worked much better than expected, such that we decided to leave the evening on the 20th. Our plan was to drive to Coldfoot, where Dirk would fly us directly to the glacier in his ski-equipped Beaver. This was the first time we tried flying in from Coldfoot, so driving as the first leg of the trip was also new for us. By 4PM we had the cars packed and we were just waiting for David to arrive from Anchorage. He called about then from the airport saying that he was indeed booked for the 4PM flight, but it was the next day's flight, thanks to my reservation-making skills. Fortunately he was able to get on a later flight, but at that point it was too late to drive. So in the end, we left on the 21st as originally planned.

We got an early start and the drive went well. We took two vehicles, both pretty well jammed full of gear, arriving about noon in Coldfoot. Dirk had another party there, also headed to about the same spot we were. Their trip had been delayed several days due to a volcano in Iceland slowing down European travel. I had talked to Dirk early in the morning about this potential conflict, and decided it would be best to send them first, as then he could scope out our landing spot and give us time to sort our gear into the two flights needed. Things went well and by evening we were well sorted and Dirk returned ready to fly us in early the next morning.

That morning we checked weather at the glacier using our telemetry and found that things looked good for a launch. So we loaded up the plane with gear, Josh, and myself, and headed off. The weather was fine, though we had to avoid a few snow squalls. The landscape was largely snow covered, but some valleys were almost blown clear, including the Hula Hula valley which we plan to focus detailed studies on in the future. Soon we were on the glacier, watching Dirk take off to get the rest of the crew and gear.

Our first priority was starting the snow machine. Landing with ski plane instead of a helicopter means that we have shuttle all of our gear up to camp, something that would take a few days on foot. The machine was partly buried in snow, but after a while of digging it out it started up on the 2nd pull. So we shuttled a load of gear to camp, hiked up the hill, and found that fortunately our caches were still in tact. In the meantime the weather had deteriorated and visibility dropped considerably. I called back to Coldfoot and found that conditions there and along the way had also deteriorated, so it looked like we would be on our own for the evening. We set up a few tents and went back for some more gear loads. By this time, having called off the next flight, the weather had cleared and we were in blue skies again. So I called back to Coldfoot and for a while we considered a late-evening flight, but in end it seemed best to wait until morning and better light on the landing surface. We set up a few more tents, ate a little dinner, and got some sleep.

The next morning was beautiful on the glacier and seemed fine along route, and a few hours later the rest of the crew was on the glacier. A few hours later, we were eating lunch after shuttling most of the gear to camp and discussing plans for field work.

The largest effort for our work this season was drilling shallow ice cores. These cores will be used to measure how much summer meltwater drips into the snowpack and refreezes there. This process of internal accumulation of ice is one of the largest unknowns in glaciology because it is so difficult to observe. Our strategy is to extract cores in about the same spot each year and measure changes in the density of an annual snow layer as it slowly gets buried year after year. As this layer gets buried, the weight of the overlying snow gradually smushes it into ice. But when surface meltwater drips into these older layers and refreezes there, it turns those layers into ice even faster than compaction alone can. By coring year after year, we can measure these processes directly and sort them out. At least that's the idea.

So Josh, David and I headed up to the coring site for a shake-down. We found that our old freezer box was now completely buried by snow. When we first built that box in 2008, it was on the surface. It's a good sign for the glacier that there is still some accumulation going on, but overall it's not nearly enough to balance the amount of melt that occurs on the rest of the glacier in summer. After some digging we managed to find all of the gear and start a test hole. Unfortunately the generator that powers the drill was not being cooperative. Without the generator, we were unable to test out the new drill motor-unit that Josh had designed. This drill has a new handle design that allows it to be operated by two people instead of one, as with the power involved it can be a handful for one person alone. Fortunately the core barrel can also be spun into the ice without a powered drill attached to it, using a T-shaped handle which a person twists to drill the core barrel down into the snow and ice. This worked pretty well, and in most respects is easier to operate than the powered unit. It certainly is a lot safer. It was also great having Josh there, as he could quickly sort out the options and even before we started pointed out that our drill as currently setup had cutting teeth on the core barrel that were misaligned with the auger flights, something that would make successful and safe drilling a challenge. A few minutes later he had these realigned and after drilling down a few meters we had a good feel of what to expect, so we headed back to camp for a good meal and a good nights sleep.

The red gas can is sitting on top of the freezer, which is completely buried by snow.

Digging out the freezer. Fortunately as a result of this trip we realized we could do without the generator, gas, and the motorized paraphernalia associated with the drill, and thus reduced clutter in the future and allowing us to work better within the spirit of this wilderness area. It's also a lot quieter this way.

Removing the dull cutter teeth, which were misaligned with the auger flights anyway, making drilling in previous years harder and more dangerous.

Drilling our first hole. Turns out to be easier to do by hand than with a motor.

The next morning, today, we got an early start and began work on our first science hole. This hole was located a few meters up glacier of the main core we took in 2008, which we are analyzing to get a climate record of the past few hundred years. Here we hope to compare the core we extract now to that previous core, but only for the upper 6-8 meters or so. Drilling went well until we hit about 3 meters, at which point the core barrel got stuck. We tried various ways to yank it out, up until the point we broke the T-handle. Things seemed a bit disappointing at this point, since are primary system was non-functional, we had now broken our primary back-up system, and our third backup (a new core barrel) was missing an adapter piece such that we could not make use of it with our existing equipment. The T-handle seemed fixable though, so I ran back to camp and returned with a drill and bits to modify the attach point that had broken and refit the handle. The barrel was still stuck in the ice, and rather than break the new handle trying to extract it, we poured some ethanol in the hole to loosen up the cuttings that were likely jamming the barrel and a few minutes later we were able to free it. Fortunately the barrel was still full of ice and as it turned out it was likely that our previous run did not pull up all of the ice it had cut, and this extra bit was what led to the jam.

With some lessons learned we moved on to our next hole. While we had similar issues here with ice being left down the hole after coring it, we were able to core all the way through the old snow layers until we pulled up glacier ice by being making shorter runs each time. So after our first day, we had finished two of our three primary holes. With this success under our belts, we feasted on a nice mexican dinner complete with margueritas and retired to bed early, looking forward to another productive day.

30 April 10, McCall Glacier

The next morning the winds had picked up a bit. We decided to hold off drilling for a few hours to see if they would calm down. It was a good decision, because instead of getting calmer, they got stronger. So we spent most of the day trying to keep the tents from shredding or blowing away. In between gusts, I prepped some new dataloggers and timelapse cameras to be deployed later in the trip. In the evening we tried watching a movie, but the noise of the wind flapping the tents was so loud we couldnt hear it.

By morning, the winds had subsided and the skies cleared, and we were treated to beautiful weather. Unfortunately while rocking down the tents during the winds of the day before, David dropped a large rock on his finger, creating a large blood blister under his nail and a big bruise on the pad on the other side. It was quite painful for him so we decided to call the doctor on the satellite phone. He recommended some minor surgery, which consisted of heating a sewing needle red hot on the stove, then melting through his nail in a few spots. This worked wonders, draining a lot of excess blood and relieving the swelling. Given the situation, we decided it would be best to avoid further injury and give the finger some time to heal. So Josh and I headed up alone to the upper cirque to try to conquer the next hole. Things went great, and we managed to drill 8 meters and vacuum seal the cores before 6PM despite the late start. In the meantime, Turner enjoyed some glacier skiing with Kristin and David, and we toasted our success in the evening over a nice dinner of bratwursts and mashed potatoes.

The perfect weather continued and the entire crew spent the next day in the upper cirque. David, Josh and I managed to core another two 8 meter holes. These last three holes were all within a few meters of each other. The idea here is to assess the differences in the subsurface on short spatial scales. With the information from these replicates, we can have more confidence that any differences in the cores we extract next year are due to actual temporal changes to the subsurface rather than just due to drilling a few meters away. For example, if these three cores are identical, then we know that any differences in the cores we take next year are due to surface meltwater percolating into the lower layers. Or, if these three cores have major differences and the ones we take next year are within the scatter of those, then we will know that our methods are insufficient to detect the changes we are looking for.

It gets a bit awkward the longer it gets, but after about this long we use a clamp to hold the drill within the hole while we pull off the upper sections and extract it in manageable pieces.

The prize -- layers of permeable firn interbedded with ice. It's how the thickness of these ice layers is changing over the next few years that we are interested in.

Vacuum-sealed cores, ready to go into the box. Vacuum sealing is especially valuable in the upper sections of the core where the snow is soft and brittle, because it locks everything into place and keeps it from disintegrating or rearranging itself in the bag.

Not the greatest core processing set up, but still functional. I was usually the slow link in the processing chain, as you can see here a new core is waiting to be pulled out of the barrel while I'm still taking notes on the last piece.

Our methods for detecting change are a bit different than in previous years, and hopefully more robust. Previously we had been largely just looking for changes in core density caused by meltwater percolation and refreezing, and doing so by cutting up the core in the field and weighing the pieces on a makeshift workspace. Now we are returning the cores to civilization intact, and making all of our measurements there. This saves a tremendous amount of field time and also allows for much more sophisticated analyses. In this case, we are no longer measuring core density by cutting and weighing, but rather using a continuous, non-destructive method which involves passing gamma rays through the core. Density is a measure of mass per volume, so measuring it typically involves weighing something with a known volume and dividing the two numberes. In the case of ice cores, however, cutting them without losing chips or nicks is exceedingly difficult, and these errors in volume become more important the smaller the ice volume used. In our case, we want to detect density changes within thin layers and some simple calculations show that the errors in volume quickly outpace the gains in spatial resolution on these scales. The gamma ray device largely circumvents all of these issues because it uses different principles in measurement, plus it allows us to greatly expand our measurement suite as we will then take these same cores and run them through the continuous melter system we used for the paleoclimate core analysis. In this system, one inserts a slice of core vertically into the machine, a hot plate on the bottom heats the ice into water, and then a set of tubes draw the meltwater into a variety of machines that measure the concentrations of about 40 elements and compounds. In this way, we will be able to study the affect of meltwater percolation on all of these chemical proxies for paleoclimate, determine which are most affected by the process, and use this information both to improve our paleoclimate interpretations and to study the percolation process itself. The only major trick is to ensure the cores get to the lab in the solid state. But if we are successful in this, we have an opportunity here to make great advances in this aspect of glaciology, and apply what we learn not only to McCall Glacier but also the giant ice sheet of Greenland where this process is becoming increasingly important due to the expansion of the wet snow in a warming climate.

While we were drilling, Kristin and Turner went on a treasure hunt with the magnatometer to try to find some equipment of a Japanese colleague that got buried by the winter snow, and then skied all the way back to camp on their own. Though roped together, Turner was able to ski down the big hill back to camp on his own and really enjoyed it. We were not far behind, and once again were well fed and in bed in at a very civilized hour.

The result of coring -- a hole. If you look closely you can see how the upper part gets wallowed out where the snow is still fresh and loose.

Turner: "After staring into that abyss, I just feel so small and insignificant in comparison to these geologic processes that have been going on for millenia and I can't help wondering how pathetic are the concerns and dramas of adults. To-morrow, and to-morrow, and to-morrow, creeps in this petty pace from day to day, to the last syllable of recorded time; and all our yesterdays have lighted fools the way to dusty death. Out, out, brief candle! Life's but a walking shadow, a poor player, that struts and frets his hour upon the stage, and then is heard no more. It is a tale told by an idiot, full of sound and fury, signifying nothing."

Once again the next morning we were treated to another beautiful day for drilling. We only had one hole remaining, repeating the first one where we got the drill barrel stuck. This time we drilled all the way down to about 9 meters, well into the glacier ice. While we drilled, Kristin and Turner sledded down the hill past us many, many times. With the final hole drilled, and Turner comfortably asleep on the sled, the four of us packaged up all of the cores into our core boxes and readied them for transport back to Fairbanks. We utilized the old freezer from the 2008 coring campaign, which was now below the surface and a little tricky to access. But it still worked great, and with it completely buried it was doing a great job of keeping the cores frozen despite air temperatures that were probably at or above freezing. We couldnt have asked for better weather for working. Once again we finished up at civilized dinner time and decided to celebrate our success with more slushy, fruity drinks and a movie that we could actually hear.

This morning the weather had deteriorated a bit, but was still fine for working. Our goal today was to wrap up work in the upper cirque, mostly digging snow pits near all of our cores and clearing out a lot of equipment and debris that had been accumulating in or around the freezer. The general idea behind the snow pits is that we want to know how much mass of snow fell over the past year and is available for melting this summer. At the end of summer, we measure how much mass remains from this snow pack. The difference between them is what melted away. Of this melt, some of it dripped into the snow layers below and some of it ran off. Actually probably most of it dripped into the older snow layers, but once this gets saturated and there is no energy left for refreezing, it begins to drain downhill. While we have no good way to measure the actual run-off, the purpose of our coring is to measure how much refroze into the snow pack. That is, by comparing the cores we take next year to the ones we took this year, any increases in density in the subsurface must have come either from this summer's melt or rain that fell on it. So another goal for today was installing another rainfall gage to backup the one that has been there for 5 years or so now. With dataloggers and weather equipment so cheap and easy to use now, it hardly pays not to have redundant equipment. While I was digging pits and installing equipment, Josh and David excavated a crater around the freezer, trying to extract some old fuel drums and other debris leftover from 2008. Storing gear in the accumulation area of a glacier is asking for trouble, as it inevitably gets buried. Josh also drilled a shallow hole at each of our coring spots to install a new pole so that we will know exactly where we drilled and can easily locate next year's holes by simply using a tape measure from this pole. Josh also inventoried our drilling gear. At this point we had a lot of excess gear, since it turned out that coring using the T-handle was easier and safer than using the power head. So we were able to haul a couple loads of gear back down to our camp cache to be flown out later, and prevent the need for such major digging activities in the future. Once again, we were finished up by normal dinner time and in bed by 8PM.

The next morning it seemed like we were in for another storm. The clouds were low, the winds were strong, and I was in no mood for spending another day getting beat in the back by the flattening cook tent. So I decided to go up to the upper cirque to take care of some data loggers and make a few measurements and let the others relax at camp. It was nice having some alone time on the glacier. I downloaded some thermistor strings I had installed about 6 years ago, and contemplated how to proceed on some newer ones that had been installed in the past year or two a bit too low to the surface and were now buried by snow and only locatable using a magnatometer. Digging down to them would create a preferential pathway for meltwater, and would largely invalidate their purpose, which is to assess the natural pathways. So leaving them undisturbed in some ways creates better measurement conditions, as at least while buried the logger boxes and rat's nest of cables will not heat up in the sun and re-radiate their surroundings to create unnatural drainage pathways. The risk is really whether the batteries will hold out. Given that I had changed them last August, I felt it was worth the risk. So hopefully they are still logging away under the snow and in summer they will become exposed so I can download the data and re-install them correctly for the long-term so that we wont run into this problem in the future. After finishing dealing with loggers, I began taking our spring mass balance measurements with our stake network. These are poles we plant in the ice or snow to gage how much snow melts or accumulates. When I started the project in 2003, we planted about 60 of these stakes, largely in positions that had existed since the late 1960s. Most of those have since melted out and I've been gradually simplifying the network to exist only in key areas so that it can be measured more quickly without compromising quality much. I've also been doubling and tripling stakes in these key areas so that these fewer measurements will be more reliable. Making a measurement consists only of using a ruler to measure how much of the stake is exposed and using a probe to measure how much snow fell over the winter. It didnt take long to make these measurements in the upper cirque, and since I had all of my datalogger tools with me, I decided to just knock out the rest of the measurements and datalogger downloads on the rest of the glacier. So I cruised down the lower cirque and then down to the confluence and terminus. It took only about 2 hours to complete it and another couple hours to fiddle with some of the weather stations that needed some maintenance. So despite the late start I was back by about 5PM, in time for dinner and good conversation. By this time, the weather had improved substantially and the winds had died down, so we were able to enjoy dinner in peace, without getting whacked by a tent flapping madly in a strong wind.

Our main weather station on the glacier, still standing after 7 years and still more or less functional.

Our lowest station on the ice. This one measures air temperature, sunshine, and ice temperatures. You can see our lowest mass balance pole too, just before the steeper drop-off to the terminus and stream. Note the blue ice -- the snow is never deeper than this here, largely due to wind scour.

Of all of the weather station data I retrieved, I think the most interesting will be that from the station in the lower cirque. Here we have a thermistor string that measures ice temperatures down to bedrock, 200 meters below the surface. This ice is gradually cooling off, and we can track this with great accuracy. The ice is cooling because the surface here has gotten much colder over the past 50 years, due to the way the snow line has risen over that time. That is, this area used to be part of the glacier where snow accumulates over time, just like the upper cirque does now, but is no longer. This accumulating snow acts like a warm blanket, protecting the ice below from the cold ambient air. It does this both through the insulating affect of the snow, but also because summer meltwater drips into in the snow and refreezes, releasing a lot of heat as it changes from water into ice. So the snow is not just a blanket, but a heated blanket, and without it the ice in the lower cirque is getting colder. Our first measurements in 2008 showed that this cold wave had propagated about halfway down, but the latest measurements show this cold wave descending even deeper (technically its not really a cold wave, but rather heat loss upwards from the bottom, but it seems more descriptive to think of it as a cold wave). As far as I know, this is the first time such a cooling process has been directly measured, at least on a valley glacier.

Andy's pollen trap contraption. I couldnt figure out whether it was working or not, but there wasnt much I could do in either case.

The weather the next day was not as beautiful as it had been for most of early part of the trip, but still quite workable. I spent the morning getting our differential GPS system working. This system works like a giant electronic tape measure with high accuracy, and works by comparing measurements at a fixed base station to those made by a roving system we carry with us. In most years we have the two units communicate via a radio system so that we can make our measurements on the glacier in real time, but the system is kind of flaky and cumbersome and in practice its a lot easier and more reliable to make the final calculation in post processing, by downloading both units and letting software make the distance calculations. It's also a lot safer to work this way, because the real-time radio system does not let you reprocess for any errors in setup you may find later, and regrettably I've found that in some past years such errors have crept in to our data set. The primary use for the real time radio system was to navigate to the same spatial spots on the glacier (to within a few centimeters) to measure the change in surface elevation there over time, but now that we are making digital elevation models using airborne lidar nearly every year, there is no reason for this. That is, these airborne techniques give us surface elevation for every square meter of the glacier, which is thousands of times more data than the 75 or so spots we used to make with the GPS. This manual process usually took a couple of full days to complete, time we now thankfully have to devote to other efforts. So now the primary use of the GPS is to measure surface velocities. Here we have about 10 sites where we have two or more poles in place. The reason we use more than one pole is that the surface velocity of the glacier changes spatially and gradually each pole migrates into a faster or slower moving part of the glacier. By measuring two or more poles, each installed into the same initial position several years apart, we can measure the local gradient in velocity thereby interpolating the velocities in-between the stakes so that we can track the velocity in a single virtual spot on the glacier. We call these index-site velocities, since we're not so much concerned with the velocity of the poles but the velocity of this index site. Just like with the mass balance stake network, I've been reducing this network to exist just at key areas of the glacier. Once we got the system running and tested, Josh, David and I headed out to the make the measurements. This was the first time Josh had made it downhill from camp since we arrived. In the end it only took about 3 hours to make the velocity measurements, and it only took that long because of the conversations we were having as I was playing tour-guide on long-term changes to the glacier and the surrounding landscape. And yet once again, we were eating dinner at dinner time and in bed by 9PM.

Turner gets a lesson in high-end GPS. Once it's up and running, it's literally easy enough for a 4 year old to do.

The weather the next morning was about the same as the day before, with some clouds and occasional snow flurries. We slept in a bit and readied equipment to take down to the stream. At the stream our primary interest is to get a sense of what happens to all of the meltwater in summer, particularly the amount of water exiting the terminus. This information ties into a larger-scale project done in cooperation with the US Fish and Wildlife Service that manages this area. Here the overall question is how will the loss of glacier ice in this region affect the downstream ecology, particularly fish that migrate into these rivers. McCall Glacier is an ideal place to chip away at the answer to this because of its long-term history of research along these lines. Studying small streams like this is tricky and doing it well is quite time-consuming, essentially requiring a lot of manpower throughout the meltseason since we do not have the resources to employ standard techniques like constructing concrete bastions to attach equipment to that will survive floods and large rolling rocks. So we do the best we can, which largely consists of installing pressure transducers and time-lapse cameras which will at least give us some qualitative (and hopefully quantitative) sense of stream dynamics. Once finished with the installations, we briefly inventoried the gear in the stream cache and considered several creative ways to dispose of 200 pounds of salt stored there for a poorly-planned experiment that never happened, but left it for another day. And once again we got a leisurely start downglacier on the snow machine and were back at camp a few hours later having finished essentially all of our work on the glacier.

We set up a time lapse camera to watch the snow melt and stream run, since we wont be there to watch it ourselves.

That night I gave a Dirk a call to make a plan for returning our ice cores to Fairbanks. He had finished up some other projects and had a pretty light schedule the next few days. So we decided to give it a try today, Tuesday. Unfortunately, the weather has not been cooperative. All morning we've had a low overcast, snow flurries, and occasional ground fog, none of which are conducive to landing aircraft on snow. So now we're basically on hold. Our plan was to get the ice cores and Josh back to Fairbanks first, then give us a day or two for the demobilization. There are a few more little projects to keep us busy, but the demobilization and inventorying is something that has to wait until nice weather, as we have to dry the tents and sort gear outside into their proper boxes. So it looks like we're in for a lazy day.

Our lazy day got complicated by the inevitably beautiful weather that began just after deciding to put off the ice core shuttle for another day. I kept in touch with Dirk throughout the day, as it was beautiful on the glacier and improving in Coldfoot, we decided to give it a try. Josh, David and I thus mobilized for the core pullout while Dirk was on his way. We drove up to the upper cirque and removed all of the ice cores from the freezer. This was getting to be a challenge in general because the freezer was slowly being buried each year and now one has to climb down into into it rather than up into it like when it was built. We had 44 core boxes weighing about 450 pounds in total. I shuttled half of them down in the snow machine while David followed behind on skiis, then returned for the other half and Josh. By the time we were finished with the second shuttle, the weather had once again inevitably began turning sour. There was high cloud layer that kept the upper ridges of the valley in and out of view, and a solid wall of fog in the lower valley that occasionally enveloped us on the skiway. We dug a pit such that we could keep the cores on glacier ice where it was still about -8C, then buried them with snow for insulation. I felt pretty confident they would survive fine here, as long as it didnt rain. We hung out for a about an hour, but soon the upper and lower cloud layers began merging and there seemed little point delaying the inevitable. Once back at camp, Kristin told us that she had just talked with Frontier on the radio and that they had just talked with Dirk who said he was turning around and heading back to Coldfoot. About then it began the snow seemed to turn to rain briefly, but as the evening wore on we got our first significant snow accumulation while we watched a movie before going to bed.

The weather next day on the glacier was beautiful -- calm winds and no clouds. Unfortunately in Coldfoot and Fairbanks the situation was much different, with low ceilings and snow flurries predicted in both places. I stayed in touch with Dirk throughout the morning as I went out to do a little more surveying in the upper cirque as the others began inventorying and packing up camp. Due to our late start and the marginal weather the first day we did GPS, we skipped the upper cirque. Here there were just a few new poles I had put in to mark our drilling locations that I wanted to survey, along with a couple of velocity poles. I installed poles at our drilling sites so that there was an absolute local reference to know where our previous work was conducted -- that is, something we could run a tape measure from. The problem with simply using a GPS to mark hole locations is that the glacier is moving, such that unless you know the velocity vector at each spot you can never really be sure where your old holes and pits are. In any case, the work went quickly there and I was soon back at camp. Here I was also doing a little more surveying, this time on rock as a means to provide validation data to compare our lidar DEMs to. By measuring the surface elevations of the rock slopes around our camp, we should be able to compare these measurements to those made by airborne lidar in 2008, 2009, and 2010 to get a better sense of accuracy of these airborne data.

By the time I was back in camp and eating some lunch, Dirk was already on his way. We continued sorting boxes and inventorying for a while, but headed down to the glacier about the time we expected him to show up. About an hour later, we heard the unmistakable drone of the Wasp Jr engine that most Beaver's are equipped with, and before long we were loading ice cores and Josh into the plane. The snow was a little sticky due to the warm temperatures, but the load was reasonably light and Dirk had no issues getting airborne and on his way to the next freezer. Unfortunately the weather in Fairbanks was bad and it was not clear whether he could actually make it in, as by the time he took off it was snowing with 1/4 mile visibility there. I called him about 7PM that night to learn that he indeed could not make it in, but had placed all of the cores in a freezer in Coldfoot.

The rest of that day and most of the next, we spent packing and breaking down camp. Perhaps ironically, these were the busiest days of the whole trip. When field work becomes so civilized that you're eating dinner at 6PM every night and in bed by 9PM, but it takes several long days to break down camp then perhaps it's too civilized. I often think that if we had a hut here then we could save a huge amount of work and expense, in terms of wear and tear on tents and risking them getting moldy, but then I also think that if we had a cabin here we would rarely leave it because we've grown so accustomed to controlling our environments indoors. I look back on places like Toolik and JIRP and see this so clearly -- the comfort of warm dry lodging changes the nature and perhaps quality of the research being conducted, and at least in those two examples the infrastructure maintenance begins consuming more resources than the science does. Still, a small cabin in our case would make many aspects of camp life more efficient, and I think as long as we dont launch into building a small city, a simple well-built structure would serve the project well in terms of both science and safety. In any case, after dinner we broke down the large white cook tent so that we could dry it out in the good weather, and of course this meant that everything in the tent needed to go somewhere to stay dry as well. So we more or less got the entire camp packed up by late that night, such that only our personal gear remained. Turner, who had been such a trooper on this whole trip, got a bonus in that rather than just a short cartoon before bed, he got to watch movies all day long since we were all so busy with packing.

Friday morning I called back to Coldfoot learn that the weather everywhere was great. So we began the final phase of packing -- our personal gear. We also had bunch of other gear that we wanted to fly off the glacier, as it was no longer needed and just taking up space. To do this, we needed to shuttle loads from the glacier and recombine them afterwards on a longer airstrip, so that each shuttle load was light enough to confidently make it off the glacier. The fear is that you may end up with more gear than can be recombined into a single load at the longer airstrip. But we estimated things as best we could and hoped for the best. Dirk arrived about noon, and he and I headed off with a gear shuttle and to do some additional work in the area.

Playing catch while standing on a rock -- he's a big boy now! It was great entertainment until he threw the ball over the edge and it got lost in the rocks hundreds of feet below...

The USFWS service who manages this Refuge has recently started a new project looking at long-term landscape and ecological change. The spatial focus of this project is the Hula Hula River, and the main scientific question is to sort out what will happen to this river once the glaciers disappear, since most of the water in this river comes from glacier melt. This of course is an idea I've been pursuing for a long time (and who everyone else seems to be cashing in on but me, but that's a separate story...) so I am quite keen to get closer to answers. In this case, we wanted to see if it would be possible to deploy some pressure transducers before the rivers actually open up. So after dropping off our shuttle load, we scoped out the rivers and learned that, as expected, the channels were still filled with ice and any deployment now would be worthless scientifically later. It was a worthwhile test, however, and interesting scientifically in that it appears that this is one of the lowest snow accumulation winters in the valleys of this region in years. Even though I havent really been tracking this in any detail, the fact that there was essentially no snow in these valleys means it has to rank among the lowest snow years, and I have seen them filled with much more snow than now in some years past. It was actually somewhat awkward for us in the we had to raise the skiis and land on wheels. What it did reinforce to me clearly though is what's really required out here are time-series of vertical air photos, several times a year over many years, to get an accurate sense of snow and aufeis dynamics out here. With these data and the new DEMs I've acquired, we can really go a long way towards understanding both snow and subterranean spring dynamics, and their role in the local water cycle. I really dont see any other way to get a handle on this, and the relatively low cost compared to the standard methods of field and instrumentation deployments is a bonus.

The mid-Jago strip. The valley was essentially blown clear of snow, and it only remained in predictable places where it would drift. The snow on the right is more like ice, and it would have taken days to chip away at it to place any instruments in the future stream channel.

At the far end of the runway in the last picture, the drift from the upper bluff meets the drift in the stream channel. While there wasnt an obvious indication of aufeis, clearly there must have been some liquid water here to turn it into ice. It may have been water draining from the tundra rather than water from a spring or river channel.

This is the Hula Hula River valley, looking north over the last foothills. It's just like the Jago in terms of low snow.

The Hula Hula River valley looking south, not much snow, but plenty of aufeis in the river channel. There was open water in some of these channels. Without time-series of high resolution air photos, I'm not sure how we would ever know what's going on out here in terms of snow melt and subterranean springs.

Anyway, once we finished on the tundra we returned to the glacier and picked up the rest of the crew, who were by now wondering whether we were returning this day. It was after 2PM by the time we left, but it was beautiful weather all the way home. We of course made a brief stop to recombine our loads, which luckily were within volume limits, and enjoyed a nice view of the mountains all the way back to Coldfoot. By now it was 6PM, and thoughts of showers and beers overrode any inclinations to spend another 5 hours in a car driving south, so we got clean, ate burgers, and enjoyed toasting each other until it was time to pack up the cars and begin the final leg of our expedition the next morning.

Perhaps the most interesting thing we saw from the air were these shiny features on the surface, something we could not see from the ground. It appears to be wind scour or polishing. We know that the strongest winds on the glacier rip through here and scour away the snow down to ice, but it was never clear to us what happens once the winds pass this rollover. Apparently they just keep going straight as the valley bends, or at least some of the stronger gusts do. These are the type of observations that only airborne platforms can observe.

Here's a closer up view of the the polishing. Note the small one up high, which runs almost perpendicular to the lower one down lower. It can't be melt, as the features dont run along with the topographic gradient. I have a small weather station within the lower one that has always been troublesome, even after replacing the logger, and I think now I know why -- just gets hammered by these winds and probably the electronics get fried by static and violent shaking.

The drive home was uneventful. The weather was still great and we made good progress. It was after 4PM before we made it to our next destination, the Silver Gulch Brewery, where more beers, burgers, and toasts were in order. We called the airlines and got David's ticket moved up to later that night, and after dropping off the gear at our house we headed to Fred Meyers to get Turner a few of his long-awaited new toys for being such a sport on the glacier, and then on to the airport to send David on to his next adventure, which entailed a drive to the east coast for a summer of fun on the beach.

Apparently we were not the first visitors to this pullout to stop and have a snack.

Once David left it was just the three of us again. We spent the evening cuddled on the futon watching Avatar on BluRay we just bought at Fred's, and woke up there the next morning with our clothes on and the TV waiting for us to push a button. I slept until after noon. Despite the civilized and mellow working environment, I guess I just had accumulated fatigue that was waiting patiently for a recharge. But I awoke with a good feeling about the project, perhaps better than ever before. This year is largely a rebuilding year in terms of setting the project on course for it's next long-term phase, and I feel confident that we're now back on solid ground in terms of making plans, eliminating uncertainties, and getting the job done. I think we still have room to improve all aspects of the project, but I feel like we've really turned a corner in the overall project as a result of our accomplishments during IPY, both in terms of the magnitude of science and methods for performing it efficiently. Only time will tell whether this is true or not, but I'm excited to find out. After nearly a decade of working out here and the many heartaches and successes of the project, I think that's saying something.

Of the dozen or more expeditions I've made to McCall Glacier, this was by far the most civilized and stress-free of all of them. We had a good plan as to what to do, we had plenty of time to do it, plenty of backup plans to keep things on track, and we were able to implement them without any unnecessary drama or conflict. I suspect this was partly due to experience and partly due to luck. Certainly part of it was also due to me being the only scientist there, such that I was free to make group plans exactly as I wished and implement them exactly as I wished. Scientifically, we got some great data and will have a lot to keep us busy in the office. It was also greatly satisfying to see that my plans for simplifying the measurement program worked so well, both in terms of efficiency and result, and that in the future should funding become very tight, we could potentially complete the baseline measurements in a day with an aircraft in close support. Having that ability in our back pockets may turn out to be a tremendous asset during potentially lean times ahead.

On a personal level, my only regret is that I didnt take enough photos. A fitting on my camera belt had broken, so I transported my camera in my backpack most of the time, and this simple inconvenience led to missing some images I would really have liked to have captured. On the positive side, I cannot express the personal satisfaction I took from seeing Turner excel and thrive here. Whether jumping from rock to rock over the 'hot lava' (which looked remarkably like snow to me) or skiing or sledding down the big hills and giving a thumbs-up and smile at the bottom, I think these mean more to me than his first steps or first words. At nearly five years old, he now owns his own memories of the place and that it appears that these are positive memories of a place that means so much to me is something worth more to me than nearly any new grant or scientific achievement. And that we can still somehow manage to find ways to do this as a family (without breaking any rules at UAF...), is a continued source of relief for the stress that it causes and of course a source of pleasure for the joy it leads to.

Freshly showered and fed, we spent the evening relaxing and enjoying each others' company in the hottest bar in Coldfoot.