Snowpack Information

TCD is engaged in a study of Rocky Mountain regional chemistry. Through sampling at different high-elevation sites through Montana, Wyoming, Idaho, Colorado, New Mexico, and Utah over the past 25 years, this project aims to obtain a composite sample of the chemistry  of annual precipitation at high elevations.



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Background: Snowpacks collect atmospheric deposition throughout the snowfall season and offer a unique opportunity to obtain a composite sample of the chemistry of most (roughly November through April) of the annual precipitation at high elevations (> 1800 meters).This project was created to sample the full snowpack at selected sites to determine sources of acid deposition to sensitive mountain watersheds. Since 1993, the project has become the most expansive and comprehensive snowpack-chemical monitoring network of its kind. Beginning with sampling fewer than 20 sites in Colorado in 1993, the network has expanded to greater than 50 locations along the Continental Divide that have been sampled each year since 1993. In the process, techniques have been developed that use robust tracers to separate and quantify local and regional sources of atmospheric deposition of airborne pollutants. Through this program, long-term trends (>20 years, generally) are being developed in snowpack chemistry that enable estimation of normal or background levels, and identification of elevated chemical concentrations at a variety of locations where atmospheric deposition of acidic compounds is a concern. The project primarily monitors federally-managed lands in the Rocky Mountain region including several protected wilderness areas in National Forests and Parks. Applications of this regional snow-chemistry work include identifying regional trends in chemical concentration and deposition as well as monitoring subregional or local effects including power-plant emissions in Colorado or snowmobile usage in Yellowstone and other areas.


  1. To develop methods to accurately represent seasonal snowpack chemistry of a variety of compounds in single, annual samples where repeated sampling is possible in subsequent years.
  2. To maintain year-to-year sampling of a core group of 50 sampling locations to develop long-term trends in atmospheric deposition throughout the region.
  3. To establish background concentrations of major ions, trace metals, and isotopes of nitrogen and sulfur in atmospheric deposition; identify areas of elevated concentrations relative to background levels.
  4. To identify probable sources of elevated atmospheric deposition to snowpacks, and identify trends in chemistry as emissions change from year-to-year. Distinguish local from regional sources.
  5. To support ongoing investigations of process-level studies of effects on sensitive ecosystems of elevated concentrations of acids and other chemicals in atmospheric deposition.
  6. To provide data for future management decisions regarding permitting new emissions sources or planning reduction of existing emissions.

Study Area: Continental Divide in Montana, Wyoming, Utah, Idaho, Colorado, and New Mexico
Period of Project: 1993 to present
Project Number: CO53100
Project Chief: Graham Sextone
Cooperator: National Park Service; U.S.D.A. Forest Service; Colorado Department of Public Health and Environment; Teton Conservation District.

Additional information is available on the expanded project website. 

Snotel data collection network

The Natural Resources Conservation Service (NRCS) installs, operates, and maintains an extensive, automated system to collect snowpack and related climatic data in the Western United States called SNOTEL (for SNOwpack TELemetry). The system evolved from NRCS's Congressional mandate in the mid-1930's "to measure snowpack in the mountains of the West and forecast the water supply." The programs began with manual measurements of snow courses; since 1980, SNOTEL has reliably and efficiently collected the data needed to produce water supply forecasts and to support the resource management activities of NRCS and others.      

Climate studies, air and water quality investigations, and resource management concerns are all served by the modern SNOTEL network. The high-elevation watershed locations and the broad coverage of the network provide important data collection opportunities to researchers, water managers, and emergency managers for natural disasters such as floods.

Wyoming SNOTEL Sites

SNOTEL Snow Water Equivalent

SNOTEL Snow Depths