The four-day storm this past week doubled the winter’s total snowpack depth, increasing it from about 55 inches to just over 106 inches and helping to clear the winter of 2011-2012 of the dubious moniker, “the driest winter on record.”
It made it by just a few inches. The snow came down heavy enough to coat Mammoth Mountain with a fine, sturdy base, and it gave thirsty plants and grasses a much-needed boost for the upcoming spring growing season.
Mammoth no longer looks like a ghost town, and property managers finally switched from raking up pine needles to shoveling snow.
More importantly, perhaps, the storm brought Mammoth Pass from 1.2 inches of total precipitation (imagine all the snow melted down to water) to 4.7 inches, or from five percent of normal for this date to 20 percent of normal.
The same pattern was even more dramatic statewide; overall, the Sierra snowpack increased from 11 percent of normal to about 40 percent of normal for this date. Snow measurement sites outside of Independence jumped from 66 percent of normal for this date to 149 percent, according to data issued by the Los Angeles Department of Water and Power.
There is still a long way to go to catch up in most of the Sierra, but the winter is still young and the pattern shows the incredible difference just one several-day storm can make, said Frank Gehrke, the State Department of Water Resources snow survey coordinator.
“This was a pretty respectable increase, with fairly reasonable accumulations,” he said. He also noted something else; something on the minds of a lot of long-time Sierra residents who make watching the weather something of a hobby. It does appear that the weather in the Sierra is getting more extreme. In other words, storms are getting more intense—and so are dry periods. In hydrological terms, the word is “intra-annual variability.”
“We are seeing greater intra-annual variability,” Gehrke said. “It seems that the swings are greater.” California is already subject to more of this intra-annual variability than most inland areas due to its close proximity to the ocean, he said.
“Weather here is already highly variable but our storms have been pretty well-distributed over the winter,” Gehrke said. “Now, if we move to more extreme events, if we miss one or more storms now, it can have a big impact.”
Gehrke has more than just filling a resort town’s hotels and ski lifts on his mind. The Sierra snowpack provides about 30 percent of all the state’s water used for agriculture, industry, landscaping, and drinking. A dry winter in the high country means trouble down lower.
Despite the admittedly still dismal numbers this year, even after last weeks storm, there’s at least one thing to celebrate. “Reservoirs in the state are still at about 114 percent of normal for April 1,” Gehrke said, thanks to the far-above average snowfall last winter.