Recent storms give Sierra snowpack a fighting chance at first measurement
Around the start of each year, California water officials make a big show out of measuring the Sierra Nevada snowpack for reporters. Tuesday’s measurement before a throng of cameras was fairly bleak: Water content in the snowpack stood at just 53 percent of average, about a third as much water as the same time last year at that site.
But as snowflakes drifted down, Frank Gehrke, director of snow surveys for the Department of Water Resources, struck a positive tone after taking the state’s first official manual snowpack reading of 2017 near Echo Summit.
“I think it’s a very encouraging start to the winter,” he said. Minutes earlier, he had traversed a snowy field on cross-country skis, plunging a hollow aluminum tube into the three-foot-deep snow at seven different points over a 200-yard stretch.
“We had pretty much bare ground here a week ago.”
The first snow water content measurement of the year at Phillips is somewhat ceremonial, and provides only a snapshot of California’s water outlook as the state enters a sixth year of drought. Snowpack is critical to that assessment because a healthy snowpack acts as an additional set of reservoirs, bolstering the state’s overall water supply. In a decent year, the snowpack contributes about 30 percent of the state’s supplies, refilling reservoirs and canals during summer and fall.
Water officials will conduct hundreds more surveys at various locations throughout the Sierra in the months ahead. So far, the trend appears to show some progress in easing drought conditions. Electronic sensors at 105 stations that monitor water content across the mountain range that towers over the eastern edge of the Central Valley showed that as of Tuesday, the state’s overall snow water content is at 70 percent of normal.
All things considered, Gehrke said he’s encouraged by the forecast for more snow this week, and he noted that the season is still young.
“We’ve got three good-producing months – January, February, March – and any one of those could produce record precipitation,” he said.
The last two winters have offered some return to normalcy in Northern California after precipitation hit record lows in 2014 and 2015. But climatologists note that much of the Sierra precipitation has fallen as rain rather than snow, coinciding with warmer winter temperatures in the mountains. The average temperature at Squaw Valley, elevation 7,200 feet, was 36 degrees between October and March during the last 10 years. The average temperature over the prior 100 years was 33 degrees, according to data kept by the Western Regional Climate Center in Reno.
“We’re in this low-elevation snow drought right now,” said the climate center’s Dan McEvoy.
Experts said it’s nearly impossible to pinpoint the cause of any one season or series of storms. But they do say climate change is expected to bring more consistently warmer winters with less snow in California, a fact that will make droughts increasingly difficult to manage.
Tuesday’s survey marks the 20th time in the last 30 years that snow water content at the Phillips site fell below historical averages for Jan. 1, according to a review of Department of Water Resources data. Around two-thirds of California, largely in the southern half of the state, remains in drought conditions, according to the U.S. Drought Monitor. Last year at this time, about 97 percent of the state was in drought.
The National Weather Service has a winter storm warning in effect through Wednesday in the Sierra. Another storm is forecast for Friday, but like many these last two seasons, it’s expected to be a relatively warm storm, with snow only at higher altitudes.