As the rest of the Sierra slides slowly into drought, Mammoth bucks the trend
California is sliding closer to a true drought after a record dry January and February failed to increase the winter snowpack, but the Mammoth area is bucking the state trend and is close to 90 percent of normal for this time of year.
Mammoth Pass is one of the locations along the spine of the Sierra range where the state and the Los Angeles Department of Water and Power take their snowpack data from and as of early this month, the snowpack was at about 34.4 inches of water content.
The normal for the pass is about 40 inches of water content. Snowpack numbers are not measured in feet, since snow can be heavy in water content or light in water content, but in inches of water—which is the only number that matters in the end.
On Mammoth Mountain, however, where snow depth is more important than how much water is in the snow, the situation is much rosier.
The mountain has received about 269 inches of snow this season, including about 13.5 inches in the past week, according to Mammoth Mountain Ski Patrol data. Compared to an average winter snowpack of about 350 inches, this brings the snowpack to the 90 percent of normal to date as noted above, and to about 79 percent of normal for the year, meaning Mammoth Mountain will be open through Memorial Day this year. But the rest of the Sierra overall—which just happens to provide about one third of all the state’s water—is much worse off, coming in at about 65 percent of normal for this time of year and at just 57 percent of normal for April 1, which is the last date such measurements are taken.
After April 1, the snowpack begins to melt, so water managers that allocate the state’s water to farms, wildlife and domestic use consider the Jan. 1 to April 1 dates to be the Sierra winter. Any snow after April 1 is difficult to count on for water managers, as it cannot be counted on to add to the snowpack for a slow release into the state’s reservoirs, versus simply melting off.
“The snowpack hasn’t actually lost much water content since the seasons’ first survey on Jan. 2, when it was at 134 percent of normal for that date, but it hasn’t continued to build as the winter has deepened because of the continuing warm weather that set in after the storms of late November and December,” said Ted Thomas, a information officer for the state Department of Water Resources.
“In other words, the snowpack has not kept pace with the calendar,” he said.
That doesn’t look likely to change. Long range forecasts by the National Weather Service do not show a wet March, so far, and the National Climate Prediction Center recently released a prediction that March would be drier than average.
A warming, drying trend is expected to kick in at the end of this week, with the next possible chance of another storm toward next weekend, according to the NWS.