Monthly Archives: March 2018

Truckee River snowpack much improved; still below average

Washoe Lake is full currently with a much healthier snowpack in the nearby Carson Range. Slide Mountain as viewed across Washoe Lake from Deadman Canyon in the State Park.

The greatly improved snowpack will improve runoff in the Truckee River and flows to Pyramid Lake this spring. The snow and rain in March did come too little and too late to push us to an average water year, however. How quickly drought conditions on the river will return depends on how rapidly the spring warms up and whether we get additional storms – never to be counted on – during the early spring. Precipitation since October 1 (the beginning of the water year) remains below normal, too, but better than the snowpack. Snow water in the end-of-season snowpack appears to be diminishing year after year, especially the lower elevation snowpack.

Washoe Lake is full currently with a much healthier snowpack in the nearby Carson Range. Slide Mountain as viewed across Washoe Lake from Deadman Canyon in the State Park.

Washoe Lake is full currently with a much healthier snowpack in the nearby Carson Range. (Slide Mountain as viewed across Washoe Lake from Deadman’s Canyon in the State Park.)

The Tahoe and Truckee River basin snowpack water content remains significantly better today than in February. Although the official water content gets counted on April 1, the numbers  won’t change too much. So for March 29, the median water equivalent in the snowpack stands at 78% in the Lake Tahoe basin and 83% in the Truckee River basin. However, total precipitation (rain and snow water equivalent) for this water year is better at  97% and 91% of normal. The Carson River basin has more water in the snowpack at 88% which matches the total precipitation percentage – 88%. Overall, the Carson River’s watershed is higher elevation than the Truckee River’s which may account for the precipitation tracking overall precipitation. 

Lake Tahoe stands at 6228.6 feet – just 6″ below its maximum legal elevation and 5.6 feet above its outlet rim. The Lake Tahoe dam controls flows out of Lake Tahoe into the Truckee River. The Lake will soon see an increase in runoff from the melting snowpack. How fast it rises will be based on flows into the Truckee River by the Federal Water Master’s office – the administrator of the Federal Court decree that governs water in the Truckee River for both California and Nevada – as well as the temperatures this spring that determine how quickly the snowpack melts.  In an average water year, Lake Tahoe sees a rise in elevation of about 3 feet over spring and early summer. Truckee River flows are running above the long-term average now at more than 2,000 cubic-feet-per-second (CFS) at Pyramid Lake.

Truckee River in Reno with flows at 2,000 CFS during the last weekend in March 2018.

Pyramid Lake may see a moderate rise if flows in the Truckee River remain high for most of the spring and diversions to the Newlands Project are small. As of February 28, 2018 Pyramid’s elevation was 3,802.37 feet elevation. Pyramid Lake’s historic elevation before the Newlands Project was built was 3,880 feet in elevation. Last year saw a significant rise in the Lake’s elevation – some 10 feet. With a less than stellar water year for 2017-18, however, Pyramid Lake’s elevation will most likely decline again. The highest elevation for Pyramid Lake in the last 25 years occurred in 1999 when it reached an elevation of 3,817 feet.

Water flows from Lake Tahoe into the Truckee River increased dramatically in the past 7 days. How long these flows from Tahoe last will be based, in part, on how rapidly the snow pack melts.

Flows from Lake Tahoe have jumped from 50 to 900 CFS in the last 7 days.

Spring Equinox Storm brings late surge in Truckee River basin snowpack

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.

First day of spring 2018; storm approaching Tahoe & Truckee River

A new storm is approaching the Tahoe and Truckee River basins on the first day of spring. Will it bring significant rain and snow to the region to help make up for the dry Dec-Jan-Feb?

As impressive as it looks, it could end up producing much more precipitation on the western side of the Sierra and along the pacific coast than here on the eastern slope of the Sierra. Heaviest precipitation forecast for the Reno area is late Wednesday into Thursday morning.

Storm approaching on first day of spring, Tuesday, 3-20-18

Storms over the past weeks have improved the snowpack, but is this anticipated storm going to be a true “Miracle March” by making up for meager snowfall and rainfall during the winter? Lake Tahoe has gained nearly a half-foot of water in the last 4 weeks and now stands at a water elevation of 6,228.25 feet – 5.25 feet above its natural rim.

Tahoe elevation has risen by nearly a half foot in the last several weeks.

The Tahoe Basin and the Truckee River basin stand at 63 and 67 percent of average for snow-water equivalent. Runoff for the remainder of the year for the Truckee River will be determined by how fast the snow melts and if there are more storms to add significantly to the snow pack. While we had a great snow pack last year, it is important for our rivers and lakes to have back-to-back good flow years to promote recovery of the river environment and needed water for Pyramid Lake that has suffered from years of drought. All of us will benefit from a big storm that brings our snowpack to closer to the long-term average.

Snow water equivalent as of March 20, 2018 for Tahoe, Truckee River, and Carson River basins