A "brutal" storm, capable of generating torrential rains and potentially deadly flooding, will hit California in the middle of the week, meteorologists warned on Tuesday.
This powerful low pressure system is expected to sweep the Pacific coast of the United States on Wednesday and Thursday, and authorities are calling on residents to prepare.
"This is truly a brutal system and it should be taken seriously," the US Weather Service (NWS) warned.
According to the NWS, the storm will cause “extensive flooding, submerged roads, landslides, falling trees, widespread power outages, immediate disruption of commerce and worst of all, probable loss of life. »
Hard hit by drought for years, the west coast has been hit for several weeks by a series of storms, which have caused near record rainfall in some places.
Parts of northern California are still suffering from the aftermath of a powerful storm that swept through on New Year's Eve, causing landslides and power outages. At least one person has died after being trapped in their car by flooding, authorities said.
On December 31, San Francisco recorded the second rainiest day in its history since the measurement was launched, with 14 centimeters of precipitation.
On Tuesday, a fine rain had already reached California. Precipitation is expected to intensify significantly on Wednesday and Thursday, with nearly 13 centimeters of rain expected in the state capital, Sacramento.
The NWS warned on Twitter of "the risk of widespread flooding and wind-related damage" in San Francisco Bay and California's central coast.
The agency advises residents of threatened regions to prepare an "emergency bag" to be able to evacuate quickly if necessary, and warns of potential mudslides or landslides.
The expected rain comes from an "atmospheric river", a narrow band in the atmosphere that carries huge amounts of moisture from the tropics.
These rivers of the sky, which concentrate volumes of water vapor equivalent to the liquid transported by certain large terrestrial rivers, are far from exceptional in winter in California.
But the current phenomenon is accompanied by a “low pressure bomb”, a system capable of dropping the pressure suddenly and very quickly, thus generating very violent winds.
While these torrential rains are welcome given the drought that has hit the American West for two decades, they are not enough and can prove problematic, according to meteorologists: dry soils have difficulty absorbing a deluge of water and this causes flash floods.