My skis glide effortlessly on the undulating snow slope. I take in a deep breath, silently in awe of the late afternoon view of endless mountains that expand before me. This is a place unlike any place I have been before. White, pristine mountain ranges. A ruggedness that you can feel in just a glance, like no one’s been here except the ptarmigans and the bears that sometimes traverse the landscape, and the Sandhill cranes that fly overhead. Blue skies open wide above, and the quiet solitude of remoteness and the smell of fresh snow give a deep sense of peace. I swear to myself: this is one of the most deeply beautiful places I have experienced. And I’ve been lucky enough to have visited some truly incredible places.
I am on Wolverine Glacier, a temperate alpine glacier in the Kenai Mountains of the south-central Alaskan coast. Wolverine Glacier is designated as a “benchmark glacier” by the United States Geological Survey (USGS) – i.e., a glacier that has been selected for long-term monitoring to investigate climate, glacier geometry, glacier mass balance, glacier motion, and stream runoff. There are five total benchmark glaciers monitored by the USGS in North America, three of which reside in Alaska. Wolverine Glacier has been monitored since 1966, and these data constitute the longest continuous set of glacier mass-balance data in North America.
Location of the benchmark glaciers monitored by the USGS (credit: USGS).
You may be wondering: why place so much concerted and longstanding effort into these several glaciers? These data are unique because they provide quantitative long-term field records. When combined with broader records and technologies, these data are used to understand glacier behavior, hydrology, and glacier response to climate change on local, regional, and global scales - which is critical to understand the impacts on sea-level rise, water resources, environmental hazards, and ecosystems.
The team taking stake measurements, snow cores, and density measurements in snow pits on the glacier.
The Science
As part of the USGS mass-balance study, the variety of measurements we took included 1) stake measurements to see how much the surface had risen or dropped since the last measurements in autumn (i.e., how much snow had melted or accumulated); 2) snow and firn cores for a) snow- and firn-density measurements, which is helpful, among other things, in knowing how much liquid-water-equivalent is stored in the snow/firn of the glacier, and b) verify the depth of the last summer surfaces; and 3) shallow ice-penetrating to determine the variability of the depth of the snow/firn across the glacier. This all contributes to those long-term records I mentioned earlier.
As for my project - two years ago, I was funded through the University of Washington to carry out a small project that I had devised, which required fieldwork on Wolverine Glacier. I had planned to travel to the glacier last year - which ended up being amidst the beginning of quarantine. The trip was disappointingly and unsurprisingly canceled due to the pandemic. As pandemic restrictions lifted and vaccination percentages increased this spring in Alaska, however, the USGS encouraged me to join them on a small 3-4-person team. I would be helping them with their mass balance measurements and would have the time to carry out my project.
I won’t say that the decision to go was very easy due to pandemic considerations, but after much deliberation, I decided to pack my gear and head to Alaska - while being exceptionally cautious. I joined a team of truly incredible individuals who were exceptional scientists, deeply giving and curious people, and wonderful teammates: Louis Sass, lead glaciologist at the USGS Anchorage; Lucas Zeller, graduate student from Colorado State University; and Douglas Brinkerhoff from the University of Montana.
This year, I don’t have to tell you that the effects of the COVID-19 pandemic have been numerous and extensive, globally and personally, economically and emotionally, sometimes passing, sometimes permanent. While the world has been turned upside down, we as a human species were and are required to keep going in a way that we haven’t known before. Within the science realm, it has been interesting – and saddening – to see the effects on scientific progress. Canceled field seasons and stalled proposals. Disconnection from our communities and teams through remote work. Effects of mental and physical health struggles. Impacts of taking on more jobs – of parenting, of schooling, of caregiving. Obviously, these effects were and are different for different people and different organizations. And, clearly, the effects on scientific progress are relatively mild compared to others suffering during this pandemic year; yet I still wanted to acknowledge them, in case you were curious. Now, you may be thinking we’ve spent so much time thinking about the pandemic, reading more about its impacts is great for being a well-informed citizen, but let’s face it, we’re tired of it. Okay, then, I hear you. Let’s dig in to the science.
Skiing down the glacier. From left to right: me, Doug, and Lucas. (Photo credit: Louis Sass)
Me taking GPS measurements while the phase-sensitive radar operates on the upper Wolverine Glacier. (Photo credit: Louis Sass)
My project is built surrounding this main question: Can we use phase-sensitive radar to determine vertical strain rates in the firn of temperate alpine glaciers? It’s a different kind of question than most scientific questions – it’s more methodological, meaning it’s focused on developing a new technique that can be used to answer a broad range of scientific questions – and can be thought of as more exploratory (and risky!).
The “gap” in research Let’s break this down a little more. What is this material called firn? Firn is the stage through which snow compacts and densifies into glacier ice. How fast it compacts and its density are important to know for many applications in glaciology – for calculations of mass loss or gain (called the mass balance) of, for example, the Antarctic or Greenland Ice Sheet from satellite altimetry measurements (which measure changes in ice-sheet height), or for knowing the age of air trapped in ice cores to understanding past climate. Understanding the mass balance of glaciers and understanding what past climate was like is essential to understanding impacts of climate change and sea-level rise.
Louis taking snow-density measurements in a snowpit.
The problem is that measuring how fast firn compacts is difficult, and computer models of the firn-compaction process show substantial discrepancies in their output of firn properties, partly because these models are “tuned” to certain specific locations and have a tough time accurately characterizing firn processes outside at a single place at each of these locations. Scientists usually have taken mechanical in-situ measurements of the firn at these locations. So how is firn-compaction usually measured then? Measuring firn-compaction rates commonly utilizes an anchor installed at the base of a borehole; subsequently, changes in the firn column height are recorded by changes in length of a cable joining the anchor and a reference marker on the buried, previous ice-sheet surface. You may be putting this together already. There is thus a need for a method to assess firn compaction more accurately over more extensive conditions.
Me taking GPS measurements while the phase-sensitive radar operates on the upper Wolverine Glacier. (Photo credit: Louis Sass)
The method
Phase-sensitive radar (a.k.a. pRES) is a type of ice-penetrating radar system. How do these systems work? These types of radars ping energy into the glacier and record the returning wave that bounces back to the system. When the outgoing wave encounters materials of different properties - such as density, impurities, or temperature contrasts between internal annual layers of snow, firn, or ice – the wave may be reflected, refracted, or scattered back to the surface. The radar system receives this returning wave, and you can basically build an image of what the glacier looks like inside, based on how long it took for the wave to return.
Why is pRES different and advantageous for my project? Okay, this gets a little technical, so feel free to jump to the next paragraph if you wish. pRES radars transmit a variable step-frequency chirp and sample the returned frequency response – unlike traditional pulsed radar systems - and pRES measures both the amplitude and phase of the return waves. This means that pRES is exceptionally precise - it can detect down to millimeters of displacement of the internal layers of the glacier, unlike traditional pulsed radar systems. It also is more advantageous than other in-situ measurements used to determine firn-compaction rates because it is rapidly deployed, it can be deployed easily across the glacier at more than one location, and has exceptional resolution, as I stated previously.
Upper: View of the upper windswept part Wolverine Glacier. Left: The icefall on Wolverine Glacier as seen from camp. Right: Me looking on at the top of an unnamed peak behind Wolverine Glacier before a ski run for fun at the end of the day.
The big picture
Let’s come back to how this links to the big picture. My hope is that my project will be helpful and have implications for several lines of study, including:
- assessing the capability of using pRES to assess firn-compaction rates, which can be applied over broad conditions -> improves calibration firn-compaction models more accurately -> more accurate mass balance of ice sheets -> sea-level rise
- assessing firn structure within Wolverine glacier -> contributes to long-term records of the glacier
- informing water transport within a temperate alpine glacier -> has downstream implications for wildlife habitat and water resources,
- develop a better understanding of the impact of meltwater on firn compaction -> links to our understanding of firn models in Greenland
Upper left: Day 1, after the helicopter dropped us off at camp. Upper right: Our tents above the incoming fog bank snaking its way up the glacier. Lower left: View from inside the hut. Lower right: The hut standing proudly against the backdrop of Wolverine Glacier.
Daily routine
I shiver as the wind seeps into my clothing, my body shocked by the sudden change in temperature from within my tent to outside in subfreezing temperatures. It is 2 am and Louis has called us to look outside. I had hurriedly unzipped my tent and peered out of the entrance - immediately to be greeted by the deeply beautiful and simultaneously mysterious aroura borealis dancing its way across the sky as a backdrop to Wolverine Glacier. My sleepy mind at first couldn’t quite believe what I was watching, an artistic wonder illuminating the sky. But perhaps that’s always what happens when setting eyes on the aurora. Surrendered to wonder. Awe-inspiring and other-worldly, in the truest sense.
Our home for the week was set up on the side of the glacier, a bedrock ridge overlooking the main trunk of Wolverine Glacier as it plunges over a steep slope via an icefall. A small hut that was rebuilt by Louis existed as the permanent residence and shelter from bad weather, and houses a few bunks, a stove, oven (yes, you saw that right!), scientific equipment, and is all powered by solar panels and propane. Luxurious! Except perhaps, full disclosure, the "restroom," which was a five-gallon bucket positioned in the back of the shed.
Upper left: Lucas looking on the the pass above Wolverine Glacier. Upper right: Louis getting ready to ski down from a side ridge. Lower left: Louis and Lucas stopping midway down to the glacier. Lower right: Louis pointing out peaks surrounding the Prince Williams Sound in the distance.
Because of the pandemic restrictions, though, we stayed in individual mountain tents on a lower ledge of the ridge. The wind would sometimes increase at night to loudly rattle the tent, and the chill of the nights sometimes would nip at my face, hands, and feet to awaken me (it isn’t Antarctica cold, but it is chilling – and yes, having a circulatory restrictive condition called Raynaud’s syndrome is not the best combination with fieldwork!). Despite this, I truly enjoyed awaking in the morning to unzip my tent to suddenly unveil the magnificence of the glacier below. I couldn’t imagine a better way to start the day.
Skidoo tracks showing our path onto the glacier.
We would then assemble our gear and meander up to the hut to make breakfast – a bowl of cereal, bagels, or muffins and eat outside with an unparalleled view of Wolverine glacier and surrounding mountains and glaciers. We would leave for the day with all our gear, ascending onto the glacier in a unique way: skidoo towing two or three of us on skis and our sled of gear. We would work all day, as daylight there was quite plentiful. Then we'd perhaps do a ski run or two for fun from some of the surrounding ridges and peaks down onto the glacier. While I was not a strong backcountry skier (that may actually be an understatement, as I had only downhill skied a handful of times before, though I was a strong cross country skier), I felt impassioned and exhilarated by careening down the steep slopes with the glacier and incredible view as a backdrop - even despite several face plants at the beginning of the trip! We would arrive back to make dinner (which consisted of pizza, tamales, or pasta), huddle around to tell or listen to stories of our mountain adventures, science, or other personal discoveries, or we would sit in silence at the edge of this seemingly dreamlike place.
In conclusion
As I am writing this, and during much of the journey on Wolverine, I tried to pinpoint what made this experience unparalleled for me. The science. Community. Unparalleled beauty. Learning, both academically and personally. Self-reliance. Teamwork. I suppose part of it stemmed from the fact that I was implementing my own research that I had brewed years before in my mind’s eye and that was finally materializing. Long days on the glacier also seemed like a remedy for my spirit, an escape from the global and personal struggle of this pandemic year. But perhaps it was being actively a part of something bigger – a part of a team of scientists, a part of the amazing research, with a sense of community. In the wide circles of time, especially after this year, these moments on the glacier came to me with a deep sense of gratitude, relief, and exhilaration. A place where I could be myself, a home in a way, even though I had never been there before.
And as I sat on the rocks that had just only melted out with the recent warm weather near camp, overlooking the rugged wilderness before me - the ice fall of Wolverine Glacier and the endless snowy mountains with many glaciers of their own snaking down into the main valley, the wind bursting in small gusts to send shivers down through my body - I was suddenly struck by some seemingly fitting wisdom I had recently read from the only book I had stuffed into my duffel bag last-minutely, by Brené Brown. She uses the wilderness as a metaphor for true belonging, which I like: “Belonging so fully to yourself that you're willing to stand alone is a wilderness -- an untamed, unpredictable place of solitude and searching. It is a place as dangerous as it is breathtaking, a place as sought after as it is feared. The wilderness can often feel unholy because we can't control it, or what people think about our choice of whether to venture into that vastness or not. But it turns out to be the place of true belonging, and it's the bravest and most sacred place you will ever stand …"
As the afternoon sun descended lower in the Alaskan sky, I scribbled down some words on my notepad to try to capture that moment.
Blankets of snow lay
across the shoulders
of mountain peaks standing tall
extending
to the horizon
in rugged stoicism.
Hush, listen
to the vacancy of solitude
that drapes the afternoon
illuminating in rich tones
the soul of the Kenai mountains.
The high-altitude wilderness
bathes you in unparalleled peace
she envelopes you
with her rough
yet soothing hands
holding you up
to new heights
to let your spirit
rest upon
the wings
of her air
knowing you belong here.
So much gratitude to Louis Sass and the USGS for letting me work with them, and to my advisor, who let me use his radar system. And as always, thanks to you for reading this.
Until next time,
Annika