Hot … er, cold … on the heels of the rainiest October on record, at our Lee Vining weather station, the Mono Lake Committee measured 21.3 inches of snow—the most snowfall in November since 1994! Almost all the snow fell between the Saturday before and the Sunday after Thanksgiving. This resulted in lots of traffic accidents due to the slippery roads combined with holiday traffic.
The total precipitation for October and November was 5.84 inches, or 43% of our annual average. All of the years since 1988 (the beginning of Lee Vining weather records) with at least 4 inches of precipitation in October–November ended up with total annual precipitation above average: 1994–1995, 1996–1997, 2002–2003, 2004–2005. And all the winters with at least 18 inches of Oct–Nov snow ended up with total snowfall of at least 80 inches (compared to a 66 inch average): 1994–1995, 1996–1997, 2004–2005. You can download this data in an MS Excel file here.
It was also Lee Vining’s coldest and windiest November since 2004 (data available here).
Mono Lake level
Mono Lake dropped a tenth of a foot in November to 6,381.6 feet above sea level. This drop is typical of a dry November—yes, dry—even though Lee Vining’s November precipitation was 174% of average, Cain Ranch is more representative of Mono Lake’s climate and it received only 77% of average precipitation. This lake level is a tenth of a foot higher than last year. Since August the lake has been within a tenth of a foot of last year’s levels. Click here for the latest lake level information.
Grant Lake Reservoir to Spill in February
Gem Lake is usually being emptied this time of year, but right now it is at one of the highest levels in decades for early December. Thanks to an October 24th rainstorm that caused the Merced River and West Walker River to almost reach flood stage, and caused large rises on the upper Tuolumne River and Mono Basin streams, reservoirs and reservoir releases are higher than usual. When combined with this year’s test of the newly recommended lower winter streamflows in Rush and Lee Vining Creeks, a lot of extra water is filling Grant Lake Reservoir. Even with Southern California Edison’s cooperation in reducing its reservoir releases, Grant Lake Reservoir is already so high that it will probably spill in February. Click here for real-time flow data.
The main concern with high winter flows being released from the reservoirs is not only the additional energy that fish must expend to fight the current, but also the possibility of flows mobilizing the spawning gravels where fish eggs are incubating. Nevertheless, it is nice to have a lot of water to worry about for a change. We know that water will reach Mono Lake (where it is badly needed) next summer when the timing of higher flows is more natural. With Grant Lake Reservoir poised to spill and Gem Lake higher than usual, the two largest reservoirs in the Mono Basin will have less of a flood control effect on the snowmelt peak flows. And that will benefit the streams and the lake.