Atmospheric River Causes Dangerous Flooding, Mudslides in California Amid Heavy Rain; Over 800,000 People Without Power

An atmospheric river has brought dangerous flash flooding, mudslides, and heavy mountain snow in several parts of California, according to the National Weather Service (NWS). Amid torrential rain, the weather hazards affected central and southern California, where a total of 800,000 people have been reported to incur power outages as of Monday, February 5.

The atmospheric river had moved into the Golden State on Sunday, February 4, when it dumped heavy rain and snow, threatening low-lying areas and even coastal communities, according to local reports. The weather service stated that coastal flooding and high surf conditions will remain a concern until Monday evening. This means that strong winds and large waves could lead to flooding.

Furthermore, strong rainfall and hazardous wind led to flight disruptions across California, including delays and cancellations at the San Francisco International Airport. Last week, US meteorologists issued a forecast that looming atmospheric rivers could fuel two of the largest storms for the current winter season in California, which heightens flood risk and snowy weather.

Atmospheric River Forecast

The atmospheric river event will continue to impact and bring life-threatening flooding rain, strong winds, heavy snow, coastal erosion, and high surf to California this week. This is according to the latest forecast of the NWS through its Weather Prediction Center (WPC) at 3:00 a.m. EST (local time) on Monday. In its short-range outlook, the WPC warned that raging floodwaters will continue for southern California on Monday.

The atmospheric river, also called the "river in the sky," is accompanied deep upper-level trough or Pacific storm system, which causes flash flooding to be focusing on southern California. This weather system will eventually move along the West Coast and move further inland, according to the NWS. In the coming hours, flooding rain is expected to continue in several counties across the state.

California Flooding and Disruption

The intense atmospheric river brings a rare high risk for flooding, including Los Angeles, Santa Barbara, and Oxnard in southern California. This comes after the WPC issued a rare Level 4 of 4 severity of excessive rainfall. This weather alert comes as the US weather authorities expect a man's worth of rainfall in Los Angeles, with a total of 3 to 6 inches of rain in central and southern California.

Mandatory evacuation orders have also been imposed for communities in the counties of Los Angeles, Santa Barbara, San Jose, and Ventura. Amid the atmospheric event, local authorities issued a warning to residents regarding deadly floods and landslides. California's inclement weather is also expected to disrupt road traffic movement and public transport.

A strong atmospheric river or "Pineapple Express" is capable of transporting moisture from the tropics near Hawaii and over to the US West Coast, according to the National Oceanic and Atmospheric Administration (NOAA). Although known for carrying large volumes of water vapor and dumping heavy rain, atmospheric rivers can also be beneficial to the local water supply, the NOAA says.