Already drenched by weeks of rain, residents of northern and central California prepared Monday for possible flooding and landslides as another round of storms pummelled the state. Six to 10 inches of rain is expected in San Francisco eastward before the storm tapers off mid-week.
The weather also has affected air travel. Flightaware.com, a website that tracks airport traffic, reported 40 flight cancellations and 19 flight delays at San Francisco International Airport (SFO) as of 7:45 a.m. local time (10:45 a.m. ET).
More than 14 million people are under a flood warning or flash flood watch and residents have been advised to prepare for evacuations. “Gather important items, documents and medications in a ‘go bag'; in case you need to evacuate quickly,” the National Weather Service in Sacramento said in an advisory.
Water was being released from the Anderson Dam in Morgan Hill, which was expected to cause downstream flooding, San Jose Mayor Sam Liccardo said on Facebook.
The strong Pacific storm is also expected to bring howling winds and mountain snow Monday to central and northern parts of California, the National Weather Service reported.
Meteorologists explain the current weather patterns by saying that as a condensed column of moisture moves inland, the water vapour sweeps over the mountains, cools and forms an "atmospheric river," bringing heavy precipitation.
Strong southerly winds with gusts of 45 to 65 mph are expected to whip through the Central Valley and surrounding foothills Sunday into Monday.
The National Weather Service said the storms carry a threat of rock and mudslides, potentially making travel dangerous.
In Orinda, east of Berkeley, PG&E crews worked over the weekend to shore up a transmission tower threatened by a possible landslide, KGO reported. The tower is so remote, crews used a helicopter to transport some of their equipment.
Roads already closed or partially blocked by mudslides on Monday included northbound State Road 1 in Santa Cruz County and Sir Francis Drake Boulevard in Martin County, authorities said on social media.
Deadly downpour
Northern California is already soaked from heavy rains that have pummeled the state since early January. More stress on levees, dams, rivers, creeks and streams is expected.
Officials are also keeping an eye on the Oroville Dam, after there were mandatory evacuations last week amid concerns an emergency spillway could fail and threaten nearby communities.
“Additional heavy rain will only make matters worse,” CNN meteorologist Derek VanDam said. “There could be flooding in places that haven’t flooded in many years. The time to take action is now.”
The new onslaught of rain in Northern California comes as Southern California dries.
“We’re effectively turning off the tap in Southern California but turning it right back up again across the northern and central parts of the state,” VanDam said.
Storms smack Texas
Meanwhile, thunderstorms backed by racing winds set off a string of tornado warnings in parts of southeast Texas on Sunday and into Monday morning, according to the National Weather Service.
The strong storms, along with intensifying wind shears, may have already produced a tornado, the agency said.
At least 100 homes were reported damaged late Sunday in San Antonio, the National Weather Service told CNN. Officials plan to send out teams Monday morning to survey losses.
Nearly 40,000 customers in the San Antonio area remain without power, CPS Energy said. Two minor injuries were reported, officials said.
In Thrall, Texas — 120 miles northeast of San Antonio — strong storms after midnight Monday caused a train to partially derail, the weather service said.
