SAN FRANCISCO (CBS SF) — The leading edge of an anticipated atmospheric river storm system arrived in the San Francisco Bay Area Tuesday evening, bringing heavy rains and high winds across the region as well as reports of snow in the North and South Bay.

The rainstorm, which is expected to last into early Wednesday, may have up to 6 inches in some areas with potential wind gusts of 20-30 mph and localized gusts of up to 60 mph.

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The winds led to thousands of power outages across the Bay Area. Pacific Gas and Electric said as of 10 p.m. Tuesday, there were 38,155 customers without power, with most of the outages in the East Bay (26,175).

The National Weather Service issued a Flash Flood Warning for Sonoma County through 11 p.m. Tuesday, saying life-threatening flooding of creeks, roads along with mudslides and debris flows in areas burned in last year’s Walbridge Fire was likely.

While Doppler radar showed some intense precipitation already falling shortly before 7 p.m., forecast models indicate that far heavier rain will arrive late Tuesday night into Wednesday morning.

Winds were steadily increasing as the storm system arrived, with one report of a gust of 36 mph within San Francisco city limits. Winds in SF could gust as high as 70 mph. Higher winds were also starting to hit the East Bay Hills.

The weather system is cold enough to deliver some rare snow to the North Bay.

Press Democrat photographer Kent Porter posted video on his Twitter page showing snow falling on Geysers Road above the Alexander Valley in Sonoma County Tuesday evening. According to the post, the snowfall happened at about 1,300 feet elevation.

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The Bay Area office of the National Weather Service posted that a light accumulation of snow was falling on Skyline Boulevard near Skyline Ridge Preserve in Santa Clara County.

PG&E was already reporting some outages due to weather Tuesday night. As of about 7 p.m., there were a total of 3,841 affected customers with most of the impact being felt on the Peninsula with 1,758 customers without power there. Outages were also reported in San Francisco (387 customers), the North Bay (760 customers), the East Bay (613 customers) and the South Bay (323 customers).

The heavy rain brought by the storm system has led to a number of evacuation orders and warnings across the region.

A flash flood warning has been issued in parts of Santa Clara County by the National Weather Service, with San Jose city officials anticipating potential flooding in the downtown and Willow Glen areas. The most affected area would likely be the Guadalupe River along Willow Street and Ross Creek in the Cherry Area, City Councilmember Dev Davis said in an email.

Authorities in Solano County and Napa County have issued evacuation warnings for portions of the LNU Lightning Complex burn scar because of potential mudslides and flash flooding.

The National Weather service issued a flash flood watch for the coastal North Bay including Point Reyes National Seashore, as well as the East Bay Hills and the Diablo Range. Intense winds accompanying a major storm moving through the East Bay Hills has prompted the closure of parks in the region for at least 48 hours.

Thousands of residents raced to get out on Tuesday ahead of potential mudslides in the Santa Cruz Mountains, though authorities said there were still some people who refused to evacuate.

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Evacuation warnings issued for areas of San Mateo and Monterey counties scarred by wildfires were upgraded to evacuation orders Tuesday due to the threat of mudslides as a series of storms approached the Bay Area.