Remember, the April 1st snowpack’s snow water equivalent (SWE) is a measure of our summer water reservoir. A previous blog described how rising spring and summer temperatures melt mountain snowpack, slowly releasing water into the Truckee River and filling reservoirs like Boca, Stampede, and Prosser. We use these for summer recreation and, more importantly, to release water into the Truckee River for the year-round water supply of Reno/Sparks.
So what was the April 1, 2021 snowpack measurement at the Mt Rose SNOTEL? The chart below is downloaded from the National Resources Conservation Service (NRCS) interactive website. Look for the black line, that is 2021 and peaks just above 20 inches. Compare with 2017, which is well above 80 inches and one of the highest measurements on record. Next try to find 2015 which is below 20 inches, and one of the lowest measurements on record. And then compare all of them with the average which is the green line just below 40 inches and marked by an “x” in the center.
And what was going at the Mt Rose snowcourse? The chart below is downloaded from the National Resources Conservation Service (NRCS) National Water & Climate Center (NWCC) interactive map. Look all the way to the right on the chart for a small blue at ~24 inches. Compare with 2017, which is the most recent high dot at ~82 inches, the highest measurement on record. And then try to find 2015 at ~13 inches, which is one of the lowest measurements on record. For reference, average snowpack for all measurements on the chart is ~34 inches.
When the snowpack measurement is below average, we start to talk about drought. Severe droughts are not new to Nevada; the most recent one occurred between about 2011 and 2017. It coincided with above-average temperatures, which intensified the drought. Warmer temperatures caused earlier snowmelt and for soil to be drier than normal. Drier soils absorb more of the melting snow than wet soils, so less flows into rivers.
An outcome of warmer temperatures, less streamflow, and drier soils is a generally drier forest environment. This should not come as a surprise. Let your mind drift back to fall 2020, when there were school closures and advisories to stay indoors. This time it was not a virus but smoke sweeping across Nevada as California experienced its worst wildfire season on record. Less snowpack means more frequent and destructive wildfires, in addition to threatened water resources.
In the months ahead, be mindful about your water use and please obey fire restrictions.