Atmospheric river aimed for California, floods likely


Atmospheric river: Map of Southern California showing possible rainfall amounts from Saturday night through Wednesday in blue and purple up to 10-plus inches.
The National Weather Service out of Los Angeles shared this graphic on X/Twitter showing the expected rainfall amounts from Saturday night through Wednesday due to an atmospheric river. These high rainfall amounts could cause substantial flooding. Remember: turn around, don’t drown. Image via NWS.

Rain, snow and winds coming to California

California is bracing for an onslaught of rain, strong winds and snow at higher elevations. An atmospheric river will bring the storm ashore starting Saturday night (February 3, 2024) with highest rainfall amounts falling Sunday and Monday. Some areas could see close to a foot of rain.

Officials have issued an evacuation warning for part of Santa Barbara County.

California has had a lower-than-average snowpack this season. It’s been too warm to snow, but this coming week the state will make up a little of the deficit at higher altitudes with the incoming storm. Mountainous area could see up to 6 feet of snow by Thursday, February 7.

California and the Pacific Northwest have already seen a lot of rain over the past week, as another atmospheric river hit the West Coast.

A lot of people are in the crosshairs of this atmospheric river. According to the Public Policy Institute of California, one in eight U.S. residents lives in California. And the population of just Southern California is more than 23 million.

What is an atmospheric river?

An atmospheric river is a long, narrow band of water vapor in the lowest part of the atmosphere. It’s like a river in the sky that releases precipitation when it hits the coast and mountains. When it encounters these landforms, the atmospheric river gets pushed upward, causing the water vapor to condense (change from a gas to a liquid) and fall to the ground. According to the USGS:

Up to 50% of California’s annual precipitation can come from atmospheric rivers.

Back-to-back atmospheric rivers make for a high flood risk. As The Conversation explained:

The first heavy downpours saturate the ground. As consecutive storms arrive, their precipitation falls on soil that can’t absorb more water. That contributes to more runoff. Rivers and streams fill up.

A historic nine consecutive atmospheric rivers hit California last winter, helping refill the reservoirs in the state. But they also brought flooding and mudslides.

Warnings from the NWS

Graphic with 3 categories showing a car underwater, a snow plow and a boat at sea with risk of dangerous situations.
The National Weather Service out of Los Angeles shared this graphic on X/Twitter urging people to prepare now for the dangers the next weather system could bring to Southern California. Image via NWS.
Graphic showing the timing of heaviest rainfall in the LA area.
According to the National Weather Service out of Los Angeles, the greatest threat for damaging and life-threatening floods will happen on Sunday and Monday. Image via NWS.

Bottom line: An atmospheric river is poised to hit California, bringing rain, wind and heavy snowfall at high altitudes. The National Weather Service warns people to take preparations.

The post Atmospheric river aimed for California, floods likely first appeared on EarthSky.



from EarthSky https://ift.tt/plWD6EK
Atmospheric river: Map of Southern California showing possible rainfall amounts from Saturday night through Wednesday in blue and purple up to 10-plus inches.
The National Weather Service out of Los Angeles shared this graphic on X/Twitter showing the expected rainfall amounts from Saturday night through Wednesday due to an atmospheric river. These high rainfall amounts could cause substantial flooding. Remember: turn around, don’t drown. Image via NWS.

Rain, snow and winds coming to California

California is bracing for an onslaught of rain, strong winds and snow at higher elevations. An atmospheric river will bring the storm ashore starting Saturday night (February 3, 2024) with highest rainfall amounts falling Sunday and Monday. Some areas could see close to a foot of rain.

Officials have issued an evacuation warning for part of Santa Barbara County.

California has had a lower-than-average snowpack this season. It’s been too warm to snow, but this coming week the state will make up a little of the deficit at higher altitudes with the incoming storm. Mountainous area could see up to 6 feet of snow by Thursday, February 7.

California and the Pacific Northwest have already seen a lot of rain over the past week, as another atmospheric river hit the West Coast.

A lot of people are in the crosshairs of this atmospheric river. According to the Public Policy Institute of California, one in eight U.S. residents lives in California. And the population of just Southern California is more than 23 million.

What is an atmospheric river?

An atmospheric river is a long, narrow band of water vapor in the lowest part of the atmosphere. It’s like a river in the sky that releases precipitation when it hits the coast and mountains. When it encounters these landforms, the atmospheric river gets pushed upward, causing the water vapor to condense (change from a gas to a liquid) and fall to the ground. According to the USGS:

Up to 50% of California’s annual precipitation can come from atmospheric rivers.

Back-to-back atmospheric rivers make for a high flood risk. As The Conversation explained:

The first heavy downpours saturate the ground. As consecutive storms arrive, their precipitation falls on soil that can’t absorb more water. That contributes to more runoff. Rivers and streams fill up.

A historic nine consecutive atmospheric rivers hit California last winter, helping refill the reservoirs in the state. But they also brought flooding and mudslides.

Warnings from the NWS

Graphic with 3 categories showing a car underwater, a snow plow and a boat at sea with risk of dangerous situations.
The National Weather Service out of Los Angeles shared this graphic on X/Twitter urging people to prepare now for the dangers the next weather system could bring to Southern California. Image via NWS.
Graphic showing the timing of heaviest rainfall in the LA area.
According to the National Weather Service out of Los Angeles, the greatest threat for damaging and life-threatening floods will happen on Sunday and Monday. Image via NWS.

Bottom line: An atmospheric river is poised to hit California, bringing rain, wind and heavy snowfall at high altitudes. The National Weather Service warns people to take preparations.

The post Atmospheric river aimed for California, floods likely first appeared on EarthSky.



from EarthSky https://ift.tt/plWD6EK

Aucun commentaire:

Enregistrer un commentaire