Click here if you’re having trouble viewing this photo gallery or video on your mobile device.
After a bone dry December, the stubborn atmospheric ridge of the Pacific Coast has broken down, the storm door has opened up, and on Monday, Californians from Redding to San Diego welcomed something we haven’t seen all winter: the Golden State’s first significant storm of the season.
San Francisco racked up its most rainfall in a calendar day — more than 3.15 inches — since 2014. Southern Big Sur got pounded by more than nearly 4.5 inches. Residents in fire-damaged regions in both the north and south faced flash flood watches and warnings, prompting evacuations in Southern California where the Thomas fire burned until nearly Christmas.
What a difference a month makes.
“It relieves that sense of ‘here we go again back in the drought,'” State Climatologist Michael Anderson said Monday. “We’ll have to see how the rest of the winter plays out, but it keeps us closer to our average precipitation, which is good. It’s just managing the extremes with the challenges of the huge fires that we had this fall and winter.”
In Northern California’s Wine Country region, where 44 people perished and nearly 9,000 structures were destroyed during October’s firestorms, home owners and public works crews have been preparing for flooding and mudslides. On Monday, they continued to sandbag near storm drains and lay lines of “straw wattles” — straw-stuffed burlap sausages that recreate natural filters and prevent the toxic stews of incinerated household materials from polluting the water supply.
“We do have crews out monitoring the burn scar areas and are scheduled to work late tonight through the heaviest rain,” Adriane Mertens, a spokeswoman for the city of Santa Rosa, said Monday. No significant flooding had been reported by midafternoon.
Still, officials say Northern California’s soils in the fire zones have fared better than Southern California’s, thanks to rain in October and November up north.
“That helped to activate some of the dormant seeds in the soils and you could get a little growth out of the burned areas. It helps to anchor the soil, which is always a good thing,” said Brian Garcia, a National Weather Service meteorologist in Monterey. “Southern California fires were later in the season. There hasn’t been time and there hasn’t been water, so this rain will wake up some of the dormant seeds. But what’s going to happen between now and then is that intense rain can cause flooding and pick up debris and run it down the hills.”
California’s five-year drought ended last winter, but the dry December had kept rainfall in Northern California cities at less than half or a third of average.
Before this week’s storm, Southern California had barely received a drop of rain since last February, creating prime conditions for December’s Thomas fire, the state’s largest in recorded history after burning 273,400 acres in Ventura and Santa Barbara counties. Students from UC Santa Barbara, which canceled classes a week before winter break, returned Monday to take their delayed finals.
Before Monday’s storm, rainfall in Los Angeles and San Diego, for instance, was 3 percent of normal, registering barely a tenth of an inch of rain in either city. By 4 p.m. Monday, a quarter-inch deluge in Los Angeles doubled its rainfall totals. Santa Barbara could receive as much as six inches by Tuesday.
With rain forecast to taper off after Tuesday’s morning commute, the storm is expected to bring 2 to 4 inches in the mountains around the Bay Area and up to two feet of snow in the Sierra. Monday, 3.15 inches fell on San Francisco, 2.56 in Oakland and 1.40 inches in San Jose, according to the National Weather Service. Another 3.27 inches fell on Santa Rosa and 2.04 on Napa.
The early-morning rain wreaked havoc on the morning commute, with a spike in crashes on Bay Area highways, according to the California Highway Patrol.
“A lot of them are caused by people following too closely,” said Sgt. Robert Nacke of the CHP.
Average rainfall for a full year in Los Angeles is just under 13 inches and in San Jose, just under 16 inches, so a few good storms can go a long way to bringing rainfall totals back to normal.
Because of last year’s wet winter, most major reservoirs remain at or above historic averages. The state’s largest, Shasta, is 71 percent full, which is 112 percent of average. Closer to the Bay Area, San Luis Reservoir between Gilroy and Los Banos, is 82 percent full, or 116 percent of average for this date.
“We haven’t dealt with this kind of rain in quite some time, so please be careful,” Garcia said. “Since the water year began Oct. 1, this is probably going to be the wettest system we’ve had so far.”
Staff writers Rick Hurd and Jason Green contributed to this report.
