Overview

The NASA SnowEx campaign is a multi-year effort to improve our ability to measure snow from space. More than a billion people rely on seasonal snow and ice melt for their water supply, and this water source is projected to decrease in the 21st century. Improving our abilities to measure snow properties from a satellite platform will help us understand how this water supply will change in the future.

I participated in the 2020-2021 winter field campaign on Cameron Pass (led by Dr. Daniel McGrath and fellow CSU Cryospheric Sciences PhD student Randall Bonnell). During weekly field surveys from December to May we collected a range of snow pack observations, including:

• Depth profiles of snow density, temperature, grain size/shape, and liquid water content from snow pits

• Snow depths from ground-penetrating radar and snow-probing

• UAV Structure-from-Motion surveys to create DEMs of the snow surface

• Continuous weather conditions from automated meteorological stations

This field season directly followed the 2020 Cameron Peak Fire which burned over 200,000 acres of high-elevation forest, making it the largest wildfire in Colorado history. Our field locations straddled the boundary between burned and unburned forest, allowing detailed investigations of the effects of wildfires on snowpacks. Ongoing field campaigns (into 2024 and beyond) will enable a long-term perspective on the post-fire recovery of mountain ecosystems.

Related links:

• https://snow.nasa.gov/campaigns/snowex/about

• https://www.nasa.gov/feature/goddard/2021/nasa-snow-campaign-wraps-for-2021

• https://www.kunc.org/science/2021-06-30/scientists-prepare-the-west-for-drought-by-measuring-water-contained-in-snowpack 

Publications:

Bonnell, R., et al. Evaluating L-band InSAR snow water equivalent retrievals with repeat ground-penetrating radar and terrestrial lidar surveys in northern Colorado. The Cryosphere, 2024. https://doi.org/10.5194/tc-18-3765-2024

McGrath, D., L. Zeller, R. Bonnell, W. Reis, S. Kampf, K. Williams, M. Okal, A. Olsen-Mikitowicz, E. Bump, M. Sears, K. Rittger. Declines in peak snow water equivalent and elevated snowmelt rates following the 2020 Cameron Peak wildfire in northern Colorado. Geophysical Research Letters, 2023. https://doi.org/10.1029/2022GL101294

McGrath, D., R. Bonnell, L. Zeller, A. Olsen‑Mikitowicz, E. Bump, R. Webb, HP. Marshall. A Time Series of Snow Density and Snow Water Equivalent Observations Derived From the Integration of GPR and UAV SfM Observations. Frontiers in Remote Sensing, 2022. https://doi.org/10.3389/frsen.2022.886747