Sunday, March 26, 2023

California flood watch issued as next atmospheric river looms – Usky News

LOS ANGELES: Flood watch notices were posted throughout northern and central California ahead of Thursday atmospheric river The storm is expected to bring heavy rains over much of the state, including the mountainous regions, which are still under almost a record low. snowfall,
The National Weather Service (NWS) issued an extreme-rainfall and flood advisory for a wide area encompassing the San Francisco Bay and the surrounding metropolitan areas of Sacramento, where about 15 million people live.
But smaller, riparian communities along many major rivers and their tributaries are also bracing for the possibility of overflowing streams from heavy rains and runoff from melting snow.
In Tulare County, Sheriff Mike Boudreaux issued an evacuation warning for homes and businesses along the Kings River that drains from the Sierra Nevada mountain range ahead of “this rain-on-snow event” on Wednesday.
Elsewhere, the NWS issued a “Prepare Now” alert for residents of the Big Sur, Carmel, Salinas and Pajaro Rivers.
The San Francisco Chronicle reported that crews were scrambling until the last minute to shore up levees weakened by flooding along the Cosmanes River south of Sacramento during the last storm earlier this year.
Heavy rain accompanied by strong winds was forecast to hit California from Thursday night into Friday, carried by a dense stream of subtropical atmospheric moisture flowing from Hawaii into the Pacific Ocean – a phenomenon also known as the “Pineapple Express”.
A flood watch was to remain in effect in some areas through Sunday morning.
The relatively warm storm system will bring rain not only to low-lying areas of northern and central California, but also to mid-elevation mountain regions struggling this week, dumping more than 100 inches (2.5 meters) back-to-back Struggling to dig out of the blizzard. ) Snow at a few places, forecasters said.
“Most of the flood concerns are for low-lying areas that are more susceptible to rapid river and stream surges,” said William Churchill, meteorologist at the NWS Weather Prediction Center. “It’s really a combination of heavy rain coming in and rapidly melting snow.”
Churchill said the melting snow would initially act as a sponge to soak up some of the excess rain, which would help slow down runoff and reduce the potential for large debris flows and mudflows.
Higher-elevation mountain areas – above about 8,000 feet (2,400 m) – were expected to receive even more snow, or snow mixed with rain, risking extensive roof damage to older structures under the increased weight of frozen precipitation. produces, he said.
Where possible, mountain residents were urged to remove some of the snow that had accumulated on their roofs before the next storm hit.
The raging deluge follows a three-week barrage of nine atmospheric river storms that swept California from late December to mid-January, causing widespread flooding as well as hundreds of mudslides, rockfalls and sinkholes across the state.
At least 20 deaths were attributed to the earlier storms, which lashed coastal areas with gale-force winds and pounding waves, washed away seaside roads and docks and toppled thousands of trees. was uprooted
The increasing frequency and intensity of storms like this one, experts say, are symptoms of human-caused climate change, triggering extreme droughts and making it more difficult to manage California’s precious water supply while mitigating the increased risks of flooding and wildfires. Let’s make
Although potentially damaging, such storms have eased a historic four-year drought in California, refilling some badly depleted reservoirs and the Sierra snowpack, an important source of fresh water for the state.


- Advertisement -

More News

Latest NEWS

- Advertisement -