Sometimes being average is really good news.
California’s statewide Sierra Nevada snow pack was exactly 100 percent of its historical average on Thursday — precisely normal for this date, with roughly two months left in the winter snow season.
While that might sound mediocre, it’s a big jump from a month ago. On Jan. 1, the snow pack was just 69 percent of its historical average. And a year ago on Jan. 31 it was only 18 percent of normal.
How much snow falls every winter is critical to California’s water picture. The snow, which forms a vast “frozen reservoir” over California’s 400-mile long Sierra mountain range, provides nearly one-third of the state’s water supply for cities and farms as it slowly melts in the spring and summer months, sending billions of gallons of clean, fresh water flowing down dozens of rivers and streams into reservoirs.
It also is key to the state’s ski industry, which suffered significantly during the 2012-16 drought that also caused residential water cutbacks from San Diego to the Bay Area, farm losses as wells and reservoir levels dropped and increased wildfire risk for five years.
“Being at the historical average is good,” said Chris Orrock, a spokesman for the state Department of Water Resources, on Thursday. “We just had a 10-day dry spell, and we’re basically right were we should be, with more snow coming in this weekend.”
Widespread rain and mountain snow is expected to begin Friday, with the heaviest precipitation Friday night and Saturday, according to forecasts.
The National Weather Service has issued a winter storm watch for the Sierra Nevada this weekend, and is projecting 1 to 3 feet of new snow will fall across the Sierra. Some areas — like Carson Pass, Ebbetts Pass and Sonora Pass — may get as much as 5 feet by Monday, the weather service said, with poor visibility expected on I-80 and Highway 50 and chain controls likely.
Up to 4 feet of new snow is expected at Donner Summit near Lake Tahoe and along the Tioga Road in Yosemite National Park by Monday.
Every winter, at the beginning of each month, state water officials and other government scientists fan out to take snow measurements at more than 260 sites, with electronic sensors and manual readings. One, at Phillips Station, in El Dorado County off Highway 50, is done with TV cameras and journalists in tow.
On Thursday, the reading at that location, which is near Sierra-at-Tahoe ski resort, showed 98 percent of the historical average. There were 50 inches of snow on the ground — double what there was there a month ago.
“It’s comforting to finally have an average year,” said John Paasch, chief of hydrology and flood control for the Department of Water Resources.
Statewide, on average, the water content of the Sierra Nevada snow was 61 percent Thursday of the April 1 historic average. At the Phillips Station site, it was 71 percent. In other words, California so far this winter has received about two-thirds of a full winter’s Sierra snowfall, with this weekend’s storms, and all of February and March still to come.
