Field work on Collier Glacier
After the new photon-counting LiDAR got a good shakedown on Crook Glacier a week ago, I ditched some of the equipment I wouldn’t need and hauled everything into the forefield of Collier Glacier, a full day of hiking with heavy packs. We spent 2 night in the ablation zone of the glacier, coped with katabatic winds and cold feet, and eventually got the data needed to show what we can do with our new instrument.
The goal for this trip was to deploy our new instrument over two nights on different locations on a glacier, measure its optical properties - scattering and absorption coefficient - and see if the measured values make sense given what is known about the location. I would also show that it is possible to collect a quite sizable chunk of data in a short amount of time, even in a remote location. This location, the Three Sisters Wilderness, is special an especially hard place to work in. Being a designated wilderness area, motorized equipment and transportation are prohibited, turning science to adventure, forcing us to strike a balance between research and respecting a fragile environment.
Collier Glacier is one of the better understood glaciers in Oregon, along with Eliot on Mount Hood. All that means is that someone has done research here before, but glaciology in the Cascades is far from the continuous monitoring efforts of the alps and parts of Alaska. At least there is good data on the glacier’s albedo - the portion of solar radiation that gets reflected by the ice and snow - and useful information on the reasons behind that, namely how local wind patterns transport dust from North Sister onto parts of the glacier.
I would use that data, measured decades ago by Keith Mountain, as a reference for the albedo I can estimate from my measurements. You see, sometimes the problem with a new measurement technique is that you have nothing to compare it to, and that is the case here. I can merely hope for some qualitative agreement with 40-something year old data.
I meet my crew for this trip at the Obsidian Trailhead. The crew consists of me, volunteers and students working for the Oregon Glacier Institute, my friend Jon Meyers who is with us in his capacity as a seasoned photographer, and writer Joal Stein, who was working on a piece on dying glaciers. Two more - researcher Matt Cooper, who has obtained a PhD by sticking optical fibers into boreholes in Greenland, and Johnny Ryan, my collaborator at the geography department in Eugene - would meet us the next day. We piggy-backed out field work onto a permit provided by the Oregon Glacier Institute. The small non-profit monitors glaciers in Oregon, but the record summer heat rendered their plan of setting up mass balance measurements on Collier moot, as traditional methods wouldn’t work anymore. So all they were left with for the summer was muling in my lasers, for which I (and my knees) were very grateful. I wouldn’t have wanted to carry in several hardcases, solar panels, batteries and 100ft of cables all by myself.
We pitched tents in the old glacier forefield. 100 years ago, this place was covered in thick glacier ice, reaching almost to the Pacific Crest Trail. Now it was an hour-long hike to get to ice, which was our daily commute. We hiked up as the sun set, gaining elevation exposed amazing views towards Mount Washington and beyond to the north, and we settled into our first field site on the edge of the glacier terminus. Between a broken cable that I had to fix right there and me confusing my filters, I did get promising data. We stayed on the glacier until after midnight, packed everything up, but left the equipment in the hardcases on the ice to move them further up the next day.
By the time we made it back to camp, we were cold, but once in my sleeping bag I couldn’t stop myself and spent another hour looking at the data, which turned out to be spectacularly better than the one we had collected on Crook the week before. But then it is a much nicer and cleaner glacier with less debris.
I slept for a few hours, but you couldn’t really call it sleeping. I rested. The tent shook in the wind coming down from the glacier, it got cold, and I didn’t really warm up until I we hiked back up in the morning.
In the morning, Matt and Johnny found us at our camp, they hadn’t quite made it the night before. They helped me move my equipment a little bit further up on the glacier into a zone that was supposedly cleaner, according to Keith Mountain’s albedo map. Matt also helped me to measure the density of the ice, information we would need later to estimate the concentration of impurities in the ice that would lead to the observed lowering of the absorption coefficient.
The second night rolled around, this time I knew my setup a little better, had a better plan what to do, and I was able to get my data - a collection of several measurements at different wavelengths, scattered over an area the size of a parking space - by 11pm, making it back with all of the equipment by midnight, for another cold night in the tent.
On the hike out, I couldn’t stop thinking that the summer reall couldn’t have gone any better. We could ideal conditions for field work, weren’t affected by wildfires, got good data, the equipment didn’t break, and within a few months I was able to not just throw together this new experiment, but also to find partners to carry out the fieldwork with.
