NASA SnowEx Overview

The NSIDC DAAC SnowEx collection includes data products from the NASA SnowEx mission. SnowEx data are collected from a series of airborne and ground campaigns in forested regions of the western United States. Temporal coverage of SnowEx data products begins in 2016 and includes subsequent campaigns. Data products are diverse, ranging from snow depth measurements to temperature readings to radar reflectivity. 

Worldwide, more than a billion people rely on seasonal snowpack and glaciers for their water supply, and snow also plays a crucial ecosystem role for vegetation and wildlife. Snow cover is one of the most reflective natural surfaces on Earth, sending much of the Sun’s energy back into space and cooling the planet. With snow cover anticipated to decrease over the course of the 21st century, accurate measurements of snow cover, its water content, and its reflectivity are important to scientists, decision makers and citizens. But accurately measuring and monitoring snow characteristics is complicated by the diverse nature of snowpack and the environments where it exists. Satellite data can provide continuous, global observations of snow cover, but require continual improvement through validation.

NASA’s Terrestrial Hydrology Program initiated SnowEx campaigns to fill knowledge gaps related to remote sensing of snow. SnowEx has endeavored to more accurately measure snow characteristics in a variety of terrains and vegetation canopies, check airborne measurements against ground-truth fieldwork, and compare remote-sensing technologies. All of these efforts are intended to inform future snow satellite mission design.

The NSIDC DAAC collection includes data products from SnowEx 2017 and SnowEx 2020.

About SnowEx 2017

SnowEx 2017 took place primarily in Grand Mesa and Senator Beck Basin, Colorado. The field campaign was designed to evaluate the sensitivity of different snow remote sensing techniques to increasing forest density at Grand Mesa, a large mesa in western Colorado, United States. Observations were collected periodically between September 2016 and July 2017, and included measurements from cloud-absorption radar, ground-penetrating radar, synthetic aperture radar, lidar, airborne video, base station and rover measurements, and snow pit measurements. Snow pit measurements were collected from 225 pits at Grand Mesa, and 40 at Senator Beck Basin.

SnowEx 2017 campaign resources

In addition to SnowEX17 data, the NSIDC DAAC offers some campaign resources from SnowEx2017.

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About SnowEx 2020

SnowEx 2020 took place primarily in Grand Mesa, with a number of small sites throughout Colorado. Observations began in August 2019. (The Covid-19 pandemic affected this campaign and delayed some activities.) SnowEx 2020 included measurements from ground-penetrating radar, multi-polarization ground penetrating radar, rover and stationary soil moisture probes, SnowMicroPen measurements, terrestrial laser scanner, snow pit measurements. Snow pit measurements were collected from 154 snow pits at Grand Mesa.

Concurrent with ground-based operations, precision flight lines enabled aircraft instruments to collect data from specific locations. Although observations came from myriad instruments, SnowEx 2020 relied primarily on three systems:

  • Compact Airborne System for Imaging the Environment (CASIE), developed at the University of Washington, gathers observations of snow surface temperatures.
  • Snow Water Equivalent Synthetic Aperture Radar and Radiometer (SWESARR), developed at NASA Goddard Space Flight Center, employs both active and passive microwave instruments to calculate snow water equivalent.
  • Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), developed at NASA Jet Propulsion Laboratory, observes varied parameters, including ice and hydrology.

The experiment also leveraged concurrent satellite observations, including data from NASA’s ICESat-2 and Terra missions, and the European Space Agency Sentinel-1 mission.


Snow water equivalent, snow depth, snow stratigraphy, snow density, snow grain size, snow/ice temperature, surface temperature, air temperature, reflectivity, seasonally frozen ground, brightness temperature, two-way travel time, radar reflectivity, lidar, radar cross-section

Geographic coverage

Western United States

Explore images from SnowEx