Flood Watch Takes Effect For Fremont As Storm Pounds NorCal

FREMONT, CA — As the atmospheric river continued to drench the Bay Area, a flood watch was set to take effect Monday evening for Fremont, weather officials announced.

The multiday weather system raised the threat of flooding and was expected to dump more than 8 feet of snow on the highest peaks in California and Nevada and drench other parts of the two states before it moves on midweek, forecasters said.

The National Weather Service said the flood watch advisory would remain in place from 4 p.m. through 10 p.m. on Monday amid the threat of flooding caused by excessive rainfall.

Drivers were urged to take caution as forecasters warned that a line of heavy rain was moving quickly through Northern California and residents could see periods of heavy rain late Monday afternoon and through the evenings.

"The band of heaviest rain [and] snow will make its way across #NorCal just in time to make the afternoon commute extra difficult," weather service officials tweeted. "Give yourself extra time to reach your destination. Mountain travel is HIGHLY discouraged through tomorrow morning. Drive Safe!"

Runoff from the downpour could result in the flooding of rivers, creeks, streams and other low-lying areas. Creeks and streams could rise out of their banks amid the storm. Drains and ditches could also become clogged with debris, weather officials warned.

Earlier on Monday, some streets and highways in the Bay Area were reportedly flooding as the storm soaked the region.

Residents in following cities were urged to brace for flooding.

• Livermore
• Scotts Valley
• Pacifica
• San Francisco
• Hayward
• Watsonville
• Fremont
• Live Oak
• Santa Cruz
• San Ramon
• Antioch
• Berkeley
• San Jose
• Blackhawk
• Walnut Creek
• Daly City
• Boulder Creek
• Concord
• Day Valley
• Pittsburg
• Pleasanton
• Oakland

"The bulk of rain is going to occur midnight Monday morning and through the day," Jan Null, who runs the private forecasting service Golden Gate Weather Services, told San Francisco Gate. "This is going to be a good 18 hours of relatively solid rain."

READ MORE: Atmospheric River Soaks Bay Area: See Rain Totals

Whaturban and Small Stream Flooding Caused By Excessive Rainfall Is Expected.. https://t.co/etjcr0YbO7 #CAwx pic.twitter.com/Mc5Qh8bIVB
— NWS Bay Area (@NWSBayArea) December 13, 2021

The Bay Area has not seen widespread rain since October's atmospheric river or "bomb cyclone" storm, which brought historic rainfall, toppled trees, flooded busy highways and homes, prompted evacuations and cut power to about 380,000 people.

The storm was expected to bring much needed moisture to the broader region that’s been gripped by drought caused by climate change. The latest U.S. drought monitor shows parts of Montana, Oregon, California, Nevada and Utah are classified as being in exceptional drought, which is the worst category.

Most western U.S. reservoirs that deliver water to states, cities, tribes, farmers and utilities rely on melted snow in the springtime.

The atmospheric river storm this week is typical for this time of the year but its especially notable because it’s the first big snow that is expected to significantly affect travel with ice and snow coating the roads, strong wind and limited visibility.

Atmospheric rivers are "relatively long, narrow regions in the atmosphere — like rivers in the sky," according to the National Oceanic and Atmospheric Administration. A bomb cyclone occurs when a storm undergoes bombogenesis, meaning it rapidly intensifies over a 24-hour period, according to NOAA.

The Associated Press contributed to this report.