Lightning, high winds buffet Sonoma County, Bay Area

A massive thunderstorm rocked Sonoma County and a wide swath of the Bay Area early Sunday morning, unleashing a rare display of summer lightning and intense winds that knocked out power to thousands and raised fire fears to a new level amid a searing heat wave.

Fire crews, who raced to douse dozens of fires ignited by the storm in the north, south and east reaches of the Bay Area, remained on vigil Sunday night to defend the region as the National Weather Service issued a red flag warning for dangerous fire conditions overnight and into Monday morning.

Thousands of lightning bolts struck ground during the pre-dawn electrical storm, the largest and longest of its type in the Bay Area in memory. It brought winds that exceeded 60 mph in the mountains and severe lightning that lit up the sky in an area that stretched from Monterey north to Geyserville and beyond, a region home to more than 7 million people.

“To get a lightning display like we saw this morning, to have this much lightning, is very rare,” said Will Pi, a National Weather Service meteorologist.

Conditions for the unusual lightning storm were created when Tropical Storm Fausto, which sits 1,000 miles away off the coast of Mexico, sent a plume of moist, ocean air barreling toward the Bay Area. The moisture slammed into a mass of hot air hovering over the state, a collision that created a midwest-style electrical storm that is rarely seen in the Bay Area.

Those same conditions persisted into Sunday evening, Pi said.

“We’re not sure it’s going to be as spectacular as this morning,” he said. “There’s plenty of moisture and instability, so the conditions are ripe.”

At least seven small fires broke out in in heat-parched forests and fields in Sonoma County during the storm, which reached its climax between 4 a.m. and 7 a.m., said Cal Fire Battalion Chief Marshall Turbeville.

A fire near Petaluma and another, near the Liberty Glen Campground, just off Rockpile Road in the Lake Sonoma Recreation Area, topped 2 acres apiece. Firefighters were still on scene at Lake Sonoma at 3:30 p.m. Sunday, more than a dozen hours after the arrival of the storm.

“It’s been a long day,” Turbeville said.

Firefighters originally had difficulty reaching the area near Lake Sonoma “because it’s out in the middle of nowhere,” said Bob Stratton, dispatch supervisor at Redcom, which handles most fire and emergency medical communication in the county. Stratton said the remote location “gives you an indication that it was a lightning strike.”

Stratton reported three other incidents in “the flats” — including two just off Todd Road, which he believed were lightning related. None involved more “a spot fire or a single tree. They’ve been taken care of already,” he said.

Turbeville said large lightning-sparked fires are rare in Sonoma County, mostly because storms like the one that rocked the region Sunday morning are uncommon. Firefighters also counted rain as an ally overnight.

“The good thing is we got a little bit of moisture, and that was probably the deciding factor,” Turbeville said. “That little bit of rain we got kind of held the fires in check so we could get to them.”

In Mendocino County, Cal Fire crews responded to a 5 acre fire in Eden Valley near Covelo and a half-acre fire near Hopland.

Law enforcement agencies and fire departments in Sonoma County received multiple calls reporting downed trees and power lines, the Sonoma County Sheriff’s Office reported.

More than 14,000 customers were without power Sunday morning in Sonoma County, PG&E reported. Blackouts were reported in north and east Santa Rosa, areas of west county, and a band that stretched from the northern edge of Windsor north to Asti.

PG&E officials could not confirm Sunday how many customers lost power within its service area, including in Sonoma County.

Equipment used by the National Weather Service to detect “cloud to ground” lightning strikes measured “thousands” of strikes in Bay Area during the storm, with Sonoma County’s share reaching 96, meteorologists at the National Weather Service said.

A federal Bureau of Land Management map showed 4,808 strikes throughout the state, with most of those strikes concentrated in the Bay Area.

Wind gusts reached 66 mph on Atlas Peak east of Napa and 48 mph on Mt. St. Helena north of Calistoga, the National Weather Service reported.

Large arcs of lightning and their accompanying, booming claps of thunder awoke sleeping residents across the Bay Area as the storm swept in from the south.

“Wild night in the San Francisco Bay Area. This is probably the most widespread and violent summer thunderstorm event in memory for Bay Area, & it's also one of the hottest nights in years. Convective gusts 60+ mph; enormous amount of (partially dry) lightning,” tweeted Daniel Swain, a climate scientist in the Institute of the Environment and Sustainability at the University of California, Los Angeles.

The National Weather Service on Sunday morning extended a red flag warning indicating higher fire danger for Sonoma County and the wider Bay Area. The warning, which began at 11 p.m. Saturday and will last through 11 a.m. Monday, was triggered by the risk of dry lightning because of fast-moving storms.

Supervisor James Gore, whose north county district has twice been scarred by large-scale wildland fires in the past three years, said the rare storm put him on edge.

“Just when you think we’ve seen it all, we get a dry lightning storm,” Gore said. “I was extremely concerned about fires.”

There were multiple fires reported around the Bay Area as dawn broke Sunday morning and temperatures were expected to rise rapidly during the day. The high on Sunday in Santa Rosa should be in the 90s, but by Monday temperatures could reach 100 degrees, the weather service said.

Staff Writer Tyler Silvy can be reached at tyler.silvy@pressdemocrat.com or 707-526-8667. On Twitter @tylersilvy. Staff Writer Austin Murphy can be reached at austin.murphy@pressdemocrat.com or 707-521-5214‬. On Twitter @ausmurph88