Montana Snow, Water and Climate

Gallatin River Basin

Snow Water Equivalent (SWE)

The amount of water contained in the snowpack. It is measured using the "Snow Pillow" at mountain SNOTEL sites, and measured by a Federal Snow Sampler at manual snowcourse measurements. It is a useful metric for gauging potential runoff from the melting of the snowpack in the Spring.

Basin-Wide Snow Water Equivalent

Basin-Wide Snow Water Equivalent - Time Series

Sub-Basin Snow Water Equivalent

Mountain Precipitation

Measured at mountain SNOTEL sites using a storage gage and at valley COOP weather stations using a combination of tipping buckets and storage gauges. Precipitation data is measured hourly at many sites, but is only collected monthly for COOP weather stations by the NRCS' Air and Water Database (AWDB). As such, data for valley precipitation stations is only available for the monthly time period. 

Mountain (SNOTEL) Water Year To Date Precipitation

Mountain (SNOTEL) Water Year to Date Precipitation Trend Graph

Air Temperature

Shown below is the daily average air temperature at mountain SNOTEL sites for the river basin as a whole. It is a mean (average) of all of the sites within the basin for each day. This allows for a simple comparison for how the region is ending for daily temperatures through time. 

Current Streamflows

Streamflow forecasts are issued by the NRCS each month from March 1st through June 1st for the Spring and Summer months. Primary forecast periods are through the end of July (eg. April 1st - July 31st). Forecasts are available in other formats and for other periods in the links below. 

Daily Streamflow Forecasts

Official streamflow forecasts are issued by the NRCS each month from March 1st through June 1st for the Spring and Summer months. Primary forecast periods are through the end of July (eg. April 1st - July 31st). The products below are experimental daily forecasts and should only be used for guidance on changing conditions that may impact official monthly forecasts.  

The Unofficial Montana Snow Survey