Rain over a two day period in Reno is always a rare event. Even less common is a spring equinox atmospheric river storm that drops nearly an inch of rain at the airport in Reno. I recorded 1.75″ of rain in NW Reno from March 20 to 22 while temperatures during the storm never dropped below 42ºF. While the storm was relatively warm and produced mostly rain below 6,000 feet, the snowpack in the Lake Tahoe and the Truckee River basins saw a significant boost. Flows in the Truckee River on Thursday afternoon surged to 4,000 cubic-feet-per-second (CFS) from 500 CFS earlier in the week. If you didn’t get down to the river, check out the video from Whitewater Park at Wingfield Park in downtown Reno yesterday.

The NRCS is now reporting a significant improvement to the area snowpack. In February the snowpack was in the 30 percent of average range. As of today (3/23/18) reports show the snowpack in the Lake Tahoe basin is 77% of the average and the Truckee River basin stands at 80% for snow-water equivalent. The Carson River is at 88%.

The National Weather Service forecasts another colder (but less wet) storm is heading into the Tahoe and Truckee basins late today and continuing into Sunday. It remains to be seen if the new anticipated storm adds significantly to the snowpack. Forecasts for next week show no precipitation with temperatures rising into the mid-60s.

Eastern Pacific circulation as of 3/23/2018 mid-day. (Click for full size)

Lake Tahoe’s water surface elevation rose continuously during the spring equinox storm to stand at 6,228.6 feet. Its legal limit is 6,229.1 feet. Depending on how much runoff results from the snowpack (and any additional snow and rain), there should be good flows from Lake Tahoe into the Truckee River this spring. One thing for sure, the dismal winter up until late February has seen a significant reversal with the late season storms.

Lake Tahoe’s water surface elevation has risen nearly a foot since early in 2018. The recent storms alone resulted in a half-foot rise.