LOS ANGELES — Powerful winds raked much of California on Monday, toppling trees, causing scattered power outages, whipping up blinding dust storms, and sending waves crashing ashore as a vigorous spring weather system swept through the state on its way across the West.
Rising winds were reported in Arizona, where 34 miles of Interstate 40 near Winslow had to be closed to traffic.
In Phoenix, blowing dust obscured the mountains surrounding the city, and at least four people were injured in a pileup when two semi-trucks jackknifed in a dust storm on Interstate 10 in southern Arizona. The injuries were not life-threatening.
Northern California was first to feel the lashing blasts, which spread to the Sacramento and San Joaquin valleys.
At least a dozen trees came down in San Francisco, police officer John Tozzini told KGO-TV, which reported that more than 20,000 utility customers lost power in the region. A swath of electrical outages occurred across the Sacramento Municipal Utility District, the Sacramento Bee reported.
The northwest-to-north winds were punctuated with gusts topping 80 mph at some Southern California points.
The blustery system was being fueled by a cold front.
“It’s just a cold, really strong upper low,” said Carol Smith, a meteorologist with the National Weather Service in Oxnard, Calif.
Whitecaps flecked the Pacific Ocean along the California coast, where gale warnings and small craft advisories were posted. Recreational boaters were warned to stay in port. Wind-driven swells slapped over the tops of breakwaters and turned waves into a churning froth under piers at points such as Santa Monica Beach and Manhattan Beach on the Los Angeles County coast.
Blowing dust forced the California Highway Patrol to close State Route 14 in the high desert Antelope Valley north of Los Angeles due to low visibility. Officer Michael Farrell said minor accidents occurred as motorists stopped on the road and were hit from behind by other cars. No major injuries were immediately reported.
Areas of the north San Fernando Valley experienced electrical outages as tree branches tangled with power lines in at least two areas, said Michelle Vargas, spokeswoman for the Los Angeles Department of Water and Power. About 740 homes in Sylmar and 15 homes in Pacoima were affected.
About 2,700 homes were without power Monday afternoon because of at least five downed utility poles in the remote desert area of Borrego Springs in San Diego County, according to Amber Albrecht, spokeswoman for San Diego Gas and Electric.
Southern California Edison reported major weather-related outages throughout the San Gabriel Valley, with the lights out for 4,178 customers in Rosemead, 2,580 in Monterey Park and 1,443 in Altadena.
In Ventura County, the power was out for 1,115 homes. Outages also affected more than 200 homes in Garden Grove and more than 80 homes in La Habra.
Air quality alerts were issued for northern Santa Barbara County and adjacent southern San Luis Obispo County because of blowing dust and sand.
The massive rush of air also had an upside. California’s main power grid manager, the Independent System Operator, reported that turbines spinning within the ISO grid produced a record of 4,196 megawatts at 6:44 p.m. Sunday. The previous record was 3,944 megawatts on March 3.