Click here if you’re unable to view the gallery on your mobile device.

Good morning! Here's a look at the simulated radar from the HRRR. Widespread rain will develop this afternoon and become heavy late this afternoon and evening. Gusty south winds will also develop making for extremely hazardous driving conditions during the PM commute. #CAwx pic.twitter.com/w7W12jgYW9 — NWS Bay Area (@NWSBayArea) January 16, 2019

An “atmospheric river” billed as the season’s biggest winter storm so far drenched the Bay Area on Wednesday, bringing strong winds that toppled trees and power lines and heavy rains that triggered flash-flood advisories and mudslides that snarled traffic in the Santa Cruz Mountains.

Forecasters expected anywhere from an inch or two of rain overnight in much of the Bay Area, and up to six inches in the North Bay and Santa Cruz Mountains.

National Weather Service Meteorologist Steve Anderson said Wednesday’s storm had the potential to be “one of the most powerful of the season.”

More than 25,000 PG&E customers had lost power as of Wednesday evening. Caltrans extended a shut down of Highway 1 in Big Sur from Mud Creek north past Paul’s Slide and up to Fuller’s Point near the Deetjen’s Big Sur Inn. Rough water on San Francisco Bay canceled ferries. And a mudslide on Highway 17 shutdown southbound traffic in the Santa Cruz Mountains, just south the Glenwood Cutoff.

Highway 17 slide update: S/B #1 lane re-opened and waiting for equipment to clear the #2 lane. Expect delays in the area. pic.twitter.com/r2OnC2xSfX — CHP Santa Cruz (@CHPscrz) January 17, 2019

The storm was blanketing the Sierra Nevada with a blizzard that prompted avalanche warnings and was expected to dump up to 5 feet of snow in the mountains overnight. The National Weather Service warned of “potentially life threatening conditions” above 7,000 feet in elevation, with winds up to 110 mph on ridge tops and high avalanche danger, and urged motorists to avoid mountain roads. The California Highway Patrol closed eastbound Interstate 80 mid-afternoon due to a truck crash.

The brunt of the storm was on track to move out of the Bay Area around midnight, Anderson said. But some showers and possible thunderstorms with 15-20 mph winds were still expected Thursday, with dry weather Friday and Saturday followed by another chance of light rain Sunday, he said.

San Jose had received 0.37 inches of rain over 24 hours by 5 p.m. Wednesday, but could eclipse a record for rainfall on Jan. 16 (1.38 inches in 1973), based on weather records going back to 1893, according to the National Weather Service. In San Francisco, where weather records date back to 1850, the record for rain on Jan. 16 is 2.46 inches in 1862. San Francisco had 0.99 inches over 24 hours as of 5 p.m. Wednesday.

In the North Bay, the little town of Venado west of Healdsburg had received 4.84 inches by 5 p.m. Wednesday.

As of 5 p.m. Wednesday around the rest of the Bay Area, Santa Rosa reported 1.94 inches, Napa 0.97, Concord 0.54, Oakland 0.73, Santa Cruz 0.39 and Boulder Creek 3.75. On the mountains, Mt. Umunhum received 3.31 inches, Mt. Diablo 2.1 inches and Mt. Tamalpais 2.05 inches.

By mid-afternoon, there were reports of the San Francisco Civic Center BART station closing for about an hour due to flooding, and scattered reports of downed trees in Saratoga, Los Gatos, Novato, Lafayette and near Half Moon Bay.

Wind gusts hit north San Mateo county hard. Crews responding to dozens of tree/wire down calls. pic.twitter.com/iTLyafAl7d — Karl Mondon (@karlmondon) January 17, 2019

The weather service issued a flash-flood advisory for streams and creeks from Big Sur to the North Bay during Wednesday afternoon and evening. Forecasters said that major rivers are not expected to flood.

The weather service issued a high hind warning from Wednesday afternoon through early Thursday morning for the coastal areas and higher terrain, where gusts of up to 60 mph are possible. The highest peaks were likely to see even higher gusts. For the lower elevations away from the coast, a wind advisory was in effect through early Thursday morning, where wind speeds of 25-35 and gusts up to 50 mph were expected.

The cold front was so strong that satellite images showed a “rope cloud” along the front line that extended 600 miles across the Pacific Ocean, Anderson said.

Worth taking another look. Impressive #GOES17. Notice the main low pressure with several small vortices rotating around it. The rope cloud continues (cold front) #cawx pic.twitter.com/l4XN1AvTAb — NWS Bay Area (@NWSBayArea) January 16, 2019

Pacific Gas and Electric had more than 100 line-workers staged and ready to respond to outages in the South Bay and Central Coast area, with a base camp in Scotts Valley to improve response to outages in the Santa Cruz Mountains, spokeswoman Mayra Tostado said. The utility had 21,294 customers around the Bay Area without power as of 5 p.m. Wednesday, mostly in the Santa Cruz Mountains, and another 4,194 along the Central Coast.

“As soon as the heavy rain hits, we’ll shift to an all-hands-on deck-situation where our focus is restoring power as quickly as possible our customers,” Tostado said.

The Scarborough Lumber hardware store in Boulder Creek was reporting brisk sales of sandbags Wednesday morning in the Santa Cruz Mountains.

A Blizzard Warning has been issued for the Sierra Wed PM-Thurs AM for elevations >7,000’. Dangerous & potentially life threatening conditions will be possible. Blizzard Warnings are saved for only the most serious situations at our office. Stay home, stay safe! #CAwx #NVwx pic.twitter.com/52nEAhq4LR — NWS Reno (@NWSReno) January 15, 2019

Atmospheric rivers are a particularly moisture-heavy, intense type of storm event. They can be 250 miles wide, 1,000 miles long and can carry 20 times as much water per second as the Mississippi River where it empties into the Gulf of Mexico.

Such storms are vital to the water supply of California and other Western states, with about a dozen significant ones providing between 25 and 50 percent of the annual water supply in most years.

We're starting to see some storm damage across the Bay Area – fortunately no one was inside this car in Novato. Track the rain here: https://t.co/Uq2FLlHdEY pic.twitter.com/LXikf1q0jJ — ABC7 News (@abc7newsbayarea) January 17, 2019

Staff writer Jason Green contributed to this report.