Understanding SWE – Peak Snowpack and Late Season

Eastern Idaho Water Rights Coalition Members:

I want to share an excellent 3 minute video I received from the Friends of the Teton River.  In this video Will Stubblefield explains how to interpret charts showing snow water equivalent or SWE.  He explains that the peak in SWE shows how much water is stored there, but SWE levels later in the spring show only how much is left. 

Last spring we had cool weather and a slow snow melt.  By May the SWE percentages to normal looked real good and many people thought that indicated the drought was over – which was not the case.  Please see this good video portrayal.  Thanks to FTR for sharing it with us.

Best, Keith

Tracking Snow Water Equivalent (SWE) is one great way to understand the state of our water supply heading into the summer. However, sometimes the percent of average SWE can be misleading or confusing depending on what time of year that metric is reported.

Just this week, our watershed has surpassed the mean annual peak of 28.2 inches of SWE! With snow and cool temps in the forecast, it is likely that our snowpack will continue to accumulate, meaning an above-average snowpack for the water year 2023.

The peak of the snow accumulation season is the best time to check in on the SWE because the annual peak gives an accurate picture of how much water has been stored in the snowpack over the whole winter. Once the snowpack starts to melt, the SWE can tell us how fast the snowpack is melting and will give a less accurate picture of the water supply when compared to the peak SWE.

Friends of the Teton River