Much of Northern CA under flood watch. How’s that different from flood warning?
As a series of winter storm systems sweeps through the West, Northern California residents are bracing for rain, mountain snow and possible flooding.
The National Weather Service issued a flood watch for much of the region on Friday, Dec. 19, warning of rising river levels, rockslides and more.
“Never drive across flooded roads,” the weather service said in a Friday post on X. “Have an evacuation plan and emergency kit.”
What’s the difference between a flood watch and a flood warning? Here’s what to know.
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Which parts of Northern California are under a flood watch?
“Flooding caused by excessive rainfall is possible” across most of Northern California, including the entire Sacramento Valley, northern San Joaquin Valley and Sierra Nevada foothills, according to the National Weather Service.
Yosemite National Park and the Yosemite Valley could also see flooding, the weather service said.
Cities affected by the flood watch include Sacramento, Modesto, Redding, Stockton and Yuba City.
It will remain in effect from 4 p.m. on Saturday, Dec. 20, through 4 p.m. on Friday, Dec. 26, according to the X post.
Which areas are at risk of flooding?
“Excessive runoff” from heavy rain could cause water levels to rise along rivers, creeks and streams in areas affected by the flood watch, according to the National Weather Service.
“Flooding may occur in low-lying, poor drainage and urban areas,” the weather service said, including “small streams and creeks.”
In addition, the agency said, “Mudslides and rockslides may occur in mountain and foothill areas.”
What’s the difference between flood watch and flood warning?
The National Weather Service uses a variety of alerts to warn residents about hazardous weather conditions.
“A flood advisory is issued when flooding is not expected to be bad enough to issue a warning,” the weather service explained on its website. “However, it may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property.”
The weather service issues a flood watch “when conditions are favorable for a specific hazardous weather event” — such as flooding — to occur, the agency explained.
“It does not mean flooding will occur, but it is possible,” the weather service said.
“A flood warning is issued when flooding is imminent or occurring,” the weather service said, indicating that it’s time to “take action.”
