Cool April maintains high elevation snowpackMay 3rd, 2011 by Greg, Information & Restoration Specialist
April in the Mono Basin was near-average, but slightly on the cool, dry, and windy side when compared to recent years. Although the high temperature on April 1st was 72 degrees F, the last two weeks struggled to get out of the 50s. It was our windiest April since 2004, with an average wind speed of 4.9 mph in Lee Vining. The 58 mph high-wind-gusts this April and last April were not out of the ordinary. You can see our April weather log here.
Lee Vining precipitation in April was between the median and mean, while precipitation at Cain Ranch was half the median and one-third of the mean. In other words, Lee Vining had close to average precipitation, but it was drier to the east.
To the west, snow surveys increased from April 1st to May 1st:
— Stanislaus: 171% to 183%
— Tuolumne: 178% to 183% (only about ½ finished)
— Merced: 172% to 199%
— San Joaquin: 178% to 197% (about 2/3 done)
The east side is lower:
— Walker: 170% to 165%
— Owens: 173% to 147% (½ done)
May 1st snow surveys are not conducted in the Mono Basin, but most nearby snow sensors showed the April 1st snow water content was maintained, and even increased in the case of Gem Pass. This is causing major delays in the plowing of Tioga Road; Yosemite National Park reports that it was the fifth-snowiest winter on record.
For Lee Vining/Mono Inn, 2011 (so far) is tied with 1995 for the fourth-snowiest season going back to 1950, after 1969, 2005, and 1983–and three more inches of snow (which happened eight times since 1950 in May–June) would put it in third place.
Mono Lake rose two tenths of a foot in April, to 6382.5 feet above sea level. This is a relatively remarkable increase for April—since the 1994 Decision 1631, only the year 2006 had as big a rise in April. The lower-elevation ephemeral streams such as Bridgeport Creek, Beartrack Creek, and Bohler Creek are partly responsible for this rise—all have contributed surface flow to Mono Lake for weeks down what are normally dry channels. Also responsible for the lake rising are high reservoir releases—this was the first year since 1945 that Grant Lake Reservoir spilled in April!
This first week of May is warmer so far, with highs near 70 predicted later in the week. That should get the snowmelt runoff going even more—and Mono Lake should rise at least 1/3 foot in May!