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A University of Washington project, aided by the Department of Energy's Atmospheric Radiation Measurement (ARM) user facility, leverages a rare confluence of collaborators to study snow sublimation.

As the impacts of climate change intensify, experts predict fundamental shifts in mountain hydrologic cycles, with consequences for snow-reliant people and ecosystems. California can serve as a case study to help connect the dots between rising temperatures and regional atmospheric patterns.

In January 2023, the Sublimation of Snow project team skied out to our field site at the Rocky Mountain Biological Laboratory for an Intensive Observation Period – a chance to validate instrument readings, align data approaches, and connect with the landscape and weather of this remarkable research location.

Field notes on the October 2022 install and reflections from the Sublimation of Snow Project Principal Investigator Jessica Lundquist.

A single snowflake hadn’t yet fallen when a team of snow researchers descended on a small town in Colorado’s Rocky Mountains this past fall. But that was intentional — they were preparing for the coming winter’s mission to answer a longstanding research question: What happens to snow after it falls?

In October, Sublimation of Snow project research partners installed a suite of field instruments to fill in data gaps on the poorly understood process of how snow behaves in windy mountain environments.

Snow sublimation, the process through which snow turns directly from a solid to a gas (water vapor) without first melting, may remove up to 90% of snowpack from the ground, but the process is not well understood. The goal of the SOS project is to improve and communicate fundamental scientific understanding of when, where, and how much snow is lost the atmosphere through sublimation.

“I've never witnessed such extreme weather events. It was the first time that I realized…how bad things could be in that region, how quickly things were changing.” -- Dr. Heïdi Sevestre, glaciologist

The decline of Arctic sea ice is an integral part of anthropogenic climate change. Sea-ice loss is already having a significant
impact on Arctic communities and ecosystems. Its role as a cause of climate changes outside of the Arctic has also attracted
much scientific interest. Evidence is mounting that Arctic sea-ice loss can affect weather and climate throughout the Northern
Hemisphere. The remote impacts of Arctic sea-ice loss can only be properly represented using models that simulate interactions
among the ocean, sea ice, land and atmosphere. A synthesis of six such experiments with different models shows consistent
hemispheric-wide atmospheric warming, strongest in the mid-to-high-latitude lower troposphere; an intensification of the
wintertime Aleutian Low and, in most cases, the Siberian High; a weakening of the Icelandic Low; and a reduction in strength
and southward shift of the mid-latitude westerly winds in winter. The atmospheric circulation response seems to be sensitive to
the magnitude and geographic pattern of sea-ice loss and, in some cases, to the background climate state. However, it is unclear
whether current-generation climate models respond too weakly to sea-ice change. We advocate for coordinated experiments
that use different models and observational constraints to quantify the climate response to Arctic sea-ice loss.