Take Home Message

Snow in the Big Wood Basin is an important storage mechanism satisfying late spring and summer water demand lower in the basin. The climate models show clear trends in the timing of snow, with more of a mixed story regarding the amount of snow expected into the future. In general, the amount of snow tends to continue the current downward trend, but there is some decade variation in this. These impacts of reduced (and earlier) snow are addressed later on in this storyline.

Key Findings

  • Snowpack has declined over the last 30 years.
  • It is difficult to identify a consistent future trend in the volume of peak snowpack across the scenarios.
  • However, all scenarios suggest a change in the timing of the peak seasonal snow (historically found near April 1) which may occur up to 6 weeks earlier.
  • High elevation snowpack, where most of the basin’s snow occurs, will be most impacted.


Snow is critical to the area because it represents water storage in the system, similar to a reservoir, and supports winter recreation. Loss of snowpack implies loss of that storage capacity, which is either gone or requires replacement in the form of man-made reservoirs. We show both the amount of snow, and the timing of the snow, to capture this storyline. Snowpack is expressed here as "Snow Water Equivalents", or SWE - the amount of water contained in snow – and is sensitive to changes in both temperature and timing of precipitation.

The Data

The following chart shows a summary of the basin average snow (SWE) on April 1 for the entire Big Wood Basin. The chart below shows similar data, but only for the high elevation ( > 6500ft) areas in the basin, for each of the climate scenarios.

Maximum Snowpack


The chart below shows the maximum SWE for the high elevation areas, expressed as decadal averages, for each of the climate scenarios. The timing of the snow is an important factor that impacts the storage of water in the snowpack into late Spring. The chart below shows the day of the year in which the maximum snowpack is reached for the high elevation areas, expressed as decadal averages, for each of the climate scenarios.




Maps depicting changes in SWE amount and distribution patterns are available here