Heavy Rainfall in California Threaten Lives and Infrastructure

Traffic makes its way along interstate 5 during a rainstorm in Santa Clarita, Calif., on Feb. 24, 2023. Marcio Jose Sanchez/AP Photo

California could see large amounts of rainfall during the weekend that could result in floods and threaten the safety of people as well as potentially cause widespread damage to infrastructure.

On Friday, over 2,400 miles from California to Hawaii are expected to come under the impact of an atmospheric river, said weather forecasting service AccuWeather. An atmospheric river is a plume of moisture that can bring heavy rain and snowfall. “During storms that pack atmospheric rivers, there is potential for a foot or more of rain to be released,” according to the service.

Since higher elevations are forecast to experience above-freezing temperatures, the snow buildup at elevations of 2,500 to 5,000 feet might not fully absorb the rain and instead get melted completely. This could result in eight to 12 inches of water getting released in a matter of hours.

As a consequence, the smaller rivers and streams on the mountains may see rapid flooding, creating a dangerous situation for people and structures in its path.

“The torrential rain and piles of snow laying at the edges of area streets and rural roads is likely to lead to flooding,” said AccuWeather Senior Meteorologist Brett Anderson in the post.

“Where possible, road crews and property owners may want to open up the storm drains to minimize the flooding risk.” Major rivers in places like Sacramento and San Joaquin could rise significantly.

AccuWeather is predicting potential urban flooding in areas near Santa Barbara to Redding. It advised motorists to be prepared for road hazards like high water, mudslides, and falling rocks. Some sections of the roads can also get washed away, the weather service warned.

Though areas from the Los Angeles basin to San Diego might avoid storm rains, these places can still get enough showers to make roads slick from Friday to Saturday.

Rainfall on Saturday, Sunday, The Week Ahead

In its March 10 update, the Weather Prediction Center (WPC) of the National Weather Service (NWS) issued a “High Risk” of excessive rainfall alert over California through Saturday morning including “severe, widespread” flash flooding.

“Areas that normally do not experience flash flooding will flood. Lives and property are in great danger from Friday into Saturday morning,” WPC said.

On Saturday, the threat of excess rainfall “reduces significantly,” due to which WPC has issued a “Marginal Risk” of excessive rainfall alert over some parts of California from Saturday into Sunday morning.

Heavy rainfall will create “localized areas” of flash flooding and affect regions that tend to experience rapid runoffs, it stated.

Meanwhile, AccuWeather is expecting more storms in the Pacific to likely make their way into California next week. “There is the potential for another atmospheric river to be tied in with a storm next week,” said AccuWeather Meteorologist Joseph Bauer.

“It appears that the storm next week will tend to spread the heavy rain throughout much of the state, and some of the downpours will extend all the way into Southern California.”

Emergency Administration Under Criticism

California’s Democrat Governor Gavin Newsom proclaimed a state of emergency in 13 counties last week due to the storms. On March 8, an additional 21 counties were brought under the purview of the emergency as the series of storms are “forecasted to continue through mid-March,’ according to a March 8 press release.

In San Bernardino, a region worst affected by the snowfall, residents criticized a lack of communication from the county as well as slow aid as people ran out of food and other supplies.

“There was no preparedness,” resident Kandice Watson told AccuWeather about planning by the county. “We haven’t been told anything.”

“We just keep getting told that we’re being sent help and that it’s on its way, but we don’t ever see anything. We see 20 dozers on the side of the highway, but they sit there for days and we sit in our houses.”