Record snowfall in Northern California may help the state’s electric grid in 2022

The deluge of snow in recent days along the Sierra Nevada mountain range has been a recordbreaker. And that's not only good news for ski resorts but it may lead to a healthy boost in hydroelectricity production in California this coming summer, which would help the state's oftenstrained electric grid.

“It's definitely been a December to remember,” said Alex Tardy, senior meteorologist at the National Weather Service. “The amount of snow has been incredible.”

The UC Berkeley Central Sierra Snow Lab, at Donner Pass and nearly 7,000 feet elevation, recorded 8 more inches of snow Wednesday morning, bringing the total for the month of December to 210 inches, the most the lab has measured for any December. Snowfall for the season thus far is at 264 inches.

On its Twitter feed, the lab posted, “We are now at 258% of our avg snowpack through this date and we have received 70% of our avg annual snowfall.”

All the snow and rain in lower elevations have boosted the water levels at reservoirs around the state.

Jeanine Jones, interstate resources manager for California's Department of Water Resources, said statewide reservoir storage Wednesday was about 78 percent of average, a 12 percent improvement compared to one month ago,

“Considering how low some of the reservoir storage was going into this season, I probably don't want to get optimistic just yet,” Jones said, “but certainly we're very happy with the conditions that we had so far because this is much better than where we were last year. Now the big question, of course, is will this continue?”

In the summer of 2021, things got about as bad as they could get for reservoirs that deliver hydroelectricity to the state's grid. The second straight year of an unrelenting drought, combined with sustained hot weather, sent water levels plunging.

Not far from Chico, the six-turbine Edward Hyatt Power Plant had to shut down operations for the first time ever in August after the water level at the Oroville Dam reservoir that feeds the plant dipped to historic lows.

Due to the limited water availability last summer, the maximum output level from California hydro facilities could only be sustained for one or two hours per day, according to the U.S. Energy Information Administration.

The numbers for 2021, compiled by the California Energy Commission, are not expected to come out until summer but the figures for 2020 — another dry and hot year — show how much hydroproduction can be affected when precipitation comes in below normal.

In-state hydroelectricity generation in 2020 dropped 44.3 percent from the year before — 21,414 gigawatt-hours from a combination of the state's large and small hydropower plants, compared to 38,494 gigawatt-hours in 2019.

Thanks to all the snow and rain in December, things are looking better for California reservoirs, although levels are still below normal.

Lake Oroville is up to 72 percent of average, as of midnight Dec. 28, according to the Department of Water Resources, or DWR for short. However, Lake Shasta — home to the state's largest reservoir — is at 49 percent of average.

Whether the rest of the winter will produce more snow and rain is a crucial question. DWR points out that California has “the most variable weather conditions in the nation.” The years 2020 and 2021 ranked as the driest two water years in state history.

And the December dump hardly means the drought is over.

“We have to wait until the snow starts to melt and hopefully we'll have a nice, gradual melt in the spring,” Tardy of the National Weather Service said. “It's still too early to celebrate but it does look fantastic for hydrogeneration, water supply and just plain getting us back closer to normal. But it's important to emphasize, it's only late December. We have a lot of winter to go and we have seen months in California where precipitation just stops.”

Long-range forecasts, Tardy said, for Southern California call a slightly below average rainfall for January through March. Northern and Central California may see about average precipitation.