More heavy Sierra snow coming this week. What it means for California drought, fires
A pair of storms will reach Northern California this week, with lighter showers Tuesday intensifying to heavy April snow in the Sierra Nevada mountains later in the week.
A winter weather advisory from the National Weather Service is already in place for the greater Lake Tahoe area, warning that between 4 and 7 inches of snow could fall at elevations of 6,500 feet and higher between 2 a.m. and 2 p.m. Tuesday.
Chain controls were in place Tuesday morning on Interstate 80 at summit level, Caltrans said.
Light to moderate rain is also expected across the Sacramento Valley on Tuesday, forecasts show.
After a brief break Tuesday night, a more ferocious bout of winter weather will begin Wednesday and hit peak intensity on Thursday.
About 1 to 2 feet of snow is expected at summit level in the central Sierra range between Wednesday and Friday morning, while up to 3 feet could fall at higher peaks, according to forecasts from the weather service’s Reno office.
Sacramento should see rain showers Wednesday and Thursday, with a chance of showers Friday. High temperatures are forecast in the mid-to-upper 60s those three days before warming to a sunny 74 degrees on Saturday and 79 by Sunday.
Sierra snow this week follows a dumping last week. The UC Berkeley Central Sierra Snow Lab in tweets Saturday said it measured 39 inches in the previous seven days, a huge amount for mid-April.
Spring snowfall has helped boost California a bit after an exceptionally dry January through March. But it’s still very unlikely to bust the drought, as the recent storms represent just a fraction of the snowpack lost to record-low precipitation earlier in the year, and the window for more heavy snow is quickly closing before summer heat arrives.
A weekly update Thursday from the U.S. Drought Monitor recorded 96% of California in at least “severe” drought status, including 47% of the state in “extreme” drought conditions, with essentially the entire Central Valley falling under the latter category.
Precipitation totals for the full water year, which began in October, have hovered for weeks around 100% of average, but those numbers don’t reflect the current picture of California’s drought, now on the brink of its third year.
Immense storms in October and December front-loaded rain and snow totals toward the beginning of the water year. But from the start of this calendar year up until this month’s winter storms, snowmelt far outpaced new snow, amid record-breaking heat and the driest three-month start to a year ever recorded.
California had entered 2022 with snowpack at 154% of the Jan. 1 average, following record snowfall in December, according to data from the state Department of Water Resources
Statewide snowpack fell as low as 22% of normal at the start of last week, then increased to 31% by Monday after last week’s storms. That’s a substantial increase for a single week in April, with another boost likely from this week’s two storms.
But it doesn’t take long for hot weather to catch up. From March 21 to March 28, snowpack faltered from 54% to 38% of normal for the date, as daytime temperatures in Northern California climbed roughly 20 degrees hotter than normal for late March.
The biggest immediate impact of the snow and wet weather are that they should help ward off Northern California’s wildfire risk, at least in the short term.
Fire agencies and climate experts have advised that this year’s wildfire season figures to be a long and difficult one for California. Less than three weeks ago, the weather service’s Sacramento office issued a red flag warning for critical fire weather – the earliest such warning ever issued for Northern California in spring, the agency said.
Storms like this week’s and last week’s should help minimize fire risk through at least the end of April, as rain and snow runoff leave fewer dry fuels susceptible to burn.
Those fuels, though, could dry back out relatively fast once warm weather returns in the near future.
