Another atmospheric river brings flood, mudslide concerns to California
Another atmospheric river is expected to bring heavy rain to most parts of California this week, raising concerns over flooding on the heels of an earlier system that broke daily rainfall records, triggered evacuations and led to multiple deaths.
The latest bout of rain will set in along the central coast of California and San Francisco Bay area by Tuesday and will continue to ramp up into Wednesday night and Thursday, according to AccuWeather.
"This atmospheric river will bring with it multiple inches of rain from the North Bay Area all the way down the coast to San Diego," said AccuWeather Meteorologist Jacob Hinson in an online forecast, adding that most areas will see 1 to 2 inches of rain by Friday.
The added rain comes as several rivers in Northern California were still near their flood stage after last week's deluge. In Southern California, large swaths of burned land from recent wildfires remain vulnerable to the rain and could quickly become sites of mudslides, forecasters warned.
Last week, San Francisco broke a daily record for rain that had been in place since 1887, with a pounding 2.53 inches of rain falling in one day, according to the National Weather Service. North of San Francisco, in Sonoma County, officials ordered evacuations as flooding destroyed homes and caused two storm-related deaths.
Danger of mudslides looms in Southern California
This week's deluge could produce floods and mudslides, forecasters said, especially in parts of Southern California that were scorched by devastating wildfires over the last month.
"While this rain will be beneficial to areas like the Central Valley and L.A. Basin, it could be too much of a good thing in certain areas. We’re still concerned about burn scars getting enough rainfall to affect soil stability, thus causing landslides or debris flows. The amount of rain in the forecast can also cause issues where drainage systems aren’t adequate, causing localized flooding of streets and roadways," Hinson said.
Outside of Los Angeles, crews were still working to clear a mudslide that cut off access to Topanga Canyon. The mudslide occurred late last month and forced officials to close sections of the Pacific Coast Highway and Topanga Canyon Road.
Much of California is experiencing dry conditions, with some parts of Southern California suffering moderate, severe and extreme drought conditions, according to the latest data from the U.S. Drought Monitor.
Storm system to dump heavy snow over the Sierra Nevada
This week's storm won't only bring rain to the Golden State. Snowfall of 6 to 12 inches could blanket across the Sierra Nevada mountain range, with some areas receiving up to 2 feet.
AccuWeather forecasters said that on Thursday "blizzard conditions across the Sierra are not out of the question."
High winds up to 40 mph are an added concern as meteorologists warn that travelers on Donner Pass could see significant delays, especially near the end of the week.
What is an atmospheric river?
Atmospheric rivers – sometimes referred to as "rivers in the sky" – are long, narrow tracts of the Earth’s atmosphere that gather moisture from the tropics near the equator and sweep it toward the poles.
According to the National Oceanic and Atmospheric Administration, atmospheric rivers can vary greatly in size and strength, however the average atmospheric river carries an amount of water vapor "roughly equivalent to the average flow of water at the mouth of the Mississippi River."
Strong atmospheric rivers can transport up to 15 times that amount.
Contributing: Elizabeth Weise, Trevor Hughes, Dinah Voyles Pulver, Paste BN