4 p.m. Friday Update(BCN): Many trees have toppled over in San Francisco today as a storm moves through the Bay Area, the city’s Department of Public Works spokeswoman Rachel Gordon said. A 20-foot tall tree was reported down on 37th Avenue between Irving and Judah streets, and other trees fell onto cars this morning on Clement Street and 44th Avenue and in the 1400 block of Kirkwood Avenue in the Bayview. No injuries were reported in any of those incidents. A large tree limb also fell on the sidewalk on Gough and California streets, Gordon said.
Southbound lanes on the Great Highway between Lincoln Way and Sloat Boulevard remain closed today because of flooding. The stretch of road along Ocean Beach closed Wednesday evening when an earlier rainstorm passed through the region. Gordon said there are crews deployed throughout the city today to clear out storm drains. They are responding to specific calls and checking on known problem areas such as Folsom and 17th streets, parts of the Richmond District and an area prone to flooding in Glen Park.
To help handle the deluge of rain, the department is offering up to 10 free sandbags for city residents and businesses. The bags can be picked up today at the DPW operations yard entrance near Marin and Kansas streets.
12:30 p.m. Friday Update: The worst of the early Friday morning storm is moving south from the Bay Area at this hour with the passage of a cold front, and the National Weather Service has canceled flood advisories for the South Bay and Santa Cruz and Monterey counties. A flash flood advisory continues for coastal and mountain areas in Big Sur.
Forecasters say we’ll see showery weather and possible thunderstorms this afternoon and evening. The storm center associated with the cold front will pass near the Big Sur coast tonight, bringing another round of rain followed by decreasing showers through Saturday afternoon. Sunday is supposed to be a dry day, but we have renewed chances of rain early next week.
The storm flooded roads throughout the region and even triggered small slides south of the Bay Area — including one on Highway 1 near Garrapata State Park, south of Carmel. As we reported earlier: PG&E is dealing with weather-related power outages involving thousands of customers in western Marin and Sonoma counties, and thousands more along the coast down to Santa Barbara County and inland to the San Joaquin Valley.
In the Sierra Nevada, where the snowpack is at just 22 percent of normal for the date, the Friday-Saturday storm is expected to drop as much as 2 feet of snow. Caltrans reports the Sierra passes are all open with chains required on small stretches of Highways 88 and 4. On the other side of the mountains, chains are required along stretches of U.S. 395 in Mono County.
The rainy weather caused more than 100 flight cancellations at San Francisco International Airport this morning, as well as flight delays of more than an hour. As of about noon, 51 arrivals and 52 departures had been canceled at SFO, airport duty manager Larry Mares said. Travelers whose flights have not been canceled are experiencing delays of about 30 to 60 minutes, with some flights delayed as much as 90 minutes.
7:30 a.m. Friday Update: As advertised, a storm that swept in from the Pacific overnight has brought high winds and heavy rain this morning. The highest rain totals from the storm, which is sending waves of precipitation across the Bay Area from the south, are being recorded in the Santa Cruz Mountains and, further down the coast, in the Santa Lucia range.
PG&E is reporting widespread power outages involving thousands of customers in western Marin and Sonoma counties, and thousands more along the coast down to Santa Barbara County and inland to the San Joaquin Valley.
The prolonged heavy rain in the South Bay prompted the National Weather Service to briefly issue a flash flood watch in an area straddling the Santa Clara, San Mateo and Santa Cruz county lines. That warning expired at 7:30 a.m.
A much wider area of the Bay Area — virtually all of the Peninsula, the South Bay and East Bay — is under a flood advisory through 8:30 a.m. (What is a flood advisory? It’s really an alert you’re going to find lots of water on roads, underpasses and the like. In the words of the National Weather Service: “A flood advisory means that although streams and creeks may be elevated or even rise out of their banks, property damage should be minimal. Inconveniences can be expected but the the flooding will not be life threatening.” Here are more weather advisory/warning definitions.)
5 p.m. Thursday Update: So, if you’re wondering: The Bay Area is in for another good blast of wet-season weather from tonight into Saturday. The incoming storm will feature high winds, with gusts up to 45 mph or higher, along the coast and in the East Bay hills. Most coastal and valley locations in the region are expected to get 1 to 2 inches of rain, with 3 to 5 inches in the hills and perhaps much higher amounts in the mountains along the Big Sur coast.
Here’s a snippet from one of our favorite pieces of periodical meteorological literature, the Area Forecast Discussion from the National Weather Service Bay Area office in Monterey:
A POWERFUL UPPER LOW AND ASSOCIATED STORM SYSTEM IS FORECAST TO MOVE TOWARD THE COAST OVERNIGHT…WITH PERSISTENT MODERATE TO HEAVY RAIN ARRIVING ALONG THE COAST RIGHT AROUND MIDNIGHT. RAIN WILL SPREAD EAST OVER THE ENTIRE AREA BY THE EARLY MORNING HOURS AS THE COLD FRONT MOVES ONSHORE BETWEEN 3 AND 6 AM. IN ADDITION TO THE RAIN…MODERATE TO STRONG SOUTHEAST WINDS WILL BE PRESENT AHEAD AND RIGHT BEHIND THE COLD FRONT. WINDS WILL INCREASE LATER THIS EVENING…PEAKING LATE TONIGHT INTO THE EARLY MORNING HOURS…WITH WIND GUSTS TO 45 MPH POSSIBLE…ESPECIALLY ALONG THE COAST AND THROUGH THE EAST BAY HILLS. A WIND ADVISORY HAS BEEN ISSUED FOR THESE AREAS AND IS VALID FROM 10 PM TONIGHT THROUGH 10 AM FRIDAY MORNING. AFTER A BRIEF BREAK IN THE WINDS LATE FRIDAY MORNING INTO FRIDAY EVENING…ANOTHER BATCH OF STRONG WINDS IS SLATED TO IMPACT THE AREA FRIDAY NIGHT INTO SATURDAY MORNING. ANOTHER WIND ADVISORY WILL LIKELY BE ISSUED DURING THE DAY SHIFT TOMORROW.
STEADY RAIN WILL BECOME SHOWERY IN ACTIVITY FRIDAY AFTERNOON AND CONTINUE INTO AT LEAST SATURDAY AFTERNOON AS THE UPPER LOW TRACKS SOUTH TOWARD SOUTHERN CA. A SLIGHT CHANCE OF THUNDERSTORMS REMAINS IN THE FORECAST FOR MAINLY RIGHT ALONG THE COAST FRIDAY MORNING INTO SATURDAY MORNING. … THUNDERSTORMS WILL BE POSSIBLE THROUGH THE ENTIRE AREA.
MOVING ONTO RAINFALL ACCUMULATION…FROM LATE TONIGHT THROUGH SATURDAY AFTERNOON…MOST VALLEY LOCATIONS WILL SEE BETWEEN AN INCH TO TWO INCHES OF RAIN…WITH THE HIGHER ELEVATIONS RECEIVING BETWEEN 2 AND 3 INCHES OF RAIN. HOWEVER…THIS WILL NOT BE THE CASE FOR THE BIG SUR COAST AS WELL AS THE SANTA CRUZ MOUNTAINS. THE SANTA CRUZ MOUNTAIN ARE FORECAST TO RECEIVE BETWEEN 3 AND 4 INCHES OF RAIN…WITH THE BIG SUR COAST RECEIVING BETWEEN 4 AND 6 INCHES OF RAIN. IT IS NOT OUT OF THE QUESTION THAT A FEW ISOLATED AREAS ALONG THE BIG SUR COAST AND SANTA LUCIA MOUNTAINS MAY RECEIVE BETWEEN 7 AND 8 INCHES OF RAIN. FLASH FLOODING WILL BE POSSIBLE ALONG THE BIG SUR COAST FROM LATE TONIGHT UNTIL FRIDAY NIGHT.
Update, 10:30 p.m. Wednesday: The main action from today’s storm has moved to the south and east of the Bay Area, and the next system is expected to bring rain to the Bay Area early Friday morning. As for the Wednesday storm totals: The National Weather Service’s long but not quite comprehensive list shows Monterey County locations got the highest amounts, with sites in the Santa Lucia Mountains inland from Big Sur getting nearly 4 inches in the past 24 hours. Many places in the Santa Cruz Mountains in the immediate Bay Area got close to 3 inches, and typically wet North Bay locations like Mount Tamalpais generally got somewhere between 1.25 and 2 inches. Bayside locations saw between half and three-quarters of an inch.
Original post: In an “ordinary” Bay Area winter, there’d be nothing at all remarkable about today’s weather. Rain? So what? In fact, confronted by a wet morning in a more typical late February, some among us might be saying, “Enough already. When does spring get here?”
But there’s nothing typical, of course, about this dry, dry winter (and yes, when it comes to California’s rainy season, variability is the norm). So that’s why we’ll assume — feel free to back us up on this — that aside from the chore of driving in the rain, the arrival of showers throughout the Bay Area this morning is cause for widespread if quiet rejoicing.
National Weather Service forecasters say the greater Bay Area — from the Sonoma-Mendocino county line down through the Salinas Valley, can expect 3 to 5 inches of rain from a series of storms between Wednesday and Saturday. Unlike the series of storms we saw earlier this month, when more than a foot of rain fell on ridgetop locations in Marin, Sonoma and Napa counties, precipitation will be more evenly distributed from north to south. The highest regional rain totals through Sunday, up to 6 inches, are forecast for the Santa Cruz Mountains and the Santa Lucia Range to the south. And the most copious precipitation statewide is expected in Southern California, where some mountain locations could see a foot of rain (or its equivalent in snow) by the end of the weekend.
As for the Sierra snowpack, forecasters say 2 to 3 feet of snow could fall over the higher elevations, with the heaviest amounts coming toward the southern end of the mountain range. The mountain snowpack, a major reservoir for the state’s annual water needs, is just 22 percent of normal for this time of year.
As to the question that hangs over any discussion of rain during a drought: How much will the current series of storms help?
Well, they won’t hurt, that’s for sure. But they will do little to make up the state’s deep precipitation deficit or prevent the water shortages we’re facing at least through the end of this calendar year. The good news is that right now forecasters are seeing increasing chances of another storm visiting the state next week.