California Governor Gavin Newsom has declared a state of emergency as storms rip through the West Coast. Over the weekend, a powerful storm is making its way across the western U.S., and the West Coast discovered what an atmospheric river is firsthand.
Los Angeles received 75 percent of its normal rainfall in a single day, leading to a saturated ground prone to flooding with a second system. This particular flooding can even be seen from space.
Atmospheric River Pours Over Nine States
The National Weather Services (NWS) issued weather warnings for nine states before the storm’s arrival, but no one expected the National Oceanic and Atmospheric Administration (NOAA) satellites to capture the atmospheric river.
“This morning, @NOAA’s #GOESWest is continuing to monitor a large #AtmosphericRiver bringing flooding rains, strong winds, and coastal flooding to southern California,” the National Oceanic and Atmospheric Administration (NOAA) posted on X, formerly Twitter, on Tuesday morning.
This Storm System Is Moving Inland
An atmospheric river is a long, narrow region in the atmosphere that transports a large amount of moisture, according to NOAA. These rivers play a major role in global climate patterns.
The atmospheric river is part of a broader storm system that is currently moving inland, according to NWS Weather Prediction Center meteorologist and forecaster Ashton Robinson Cook (via Newsweek).
What Causes Atmospheric Rivers?
Several factors cause atmospheric rivers. Wind patterns transport warm water sources mixed with warm, moist air. As air travels toward the poles, the upward motion cools the air, causing water vapor to condense into tiny water droplets or ice crystals.
Fast-moving air current guides and shapes the movement of the moist air creating a narrow, elongated “river” appearance of atmospheric rivers. The specific intensity and impact of an atmospheric river depend on various factors like temperature, wind speed, and the shape of the terrain.
Space Can See This Storm
The post continues to read: “The system is also bringing the threat of heavy mountain snow to parts of the Great Basin and southern Rockies. Satellite images with the post showed the storm swirling from the Mexico border to the Canadian border in Montana.
“Eventually, this system will slide into the interior western U.S. and is a big part of the reason for the snow to pick up, especially in the higher territory of Arizona northward through Wyoming,” Robinson Cook said to Newsweek.
How Is the Weather Affecting People
The Los Angeles Fire Department said 1,000 firefighters are fighting against 49 debris flows, 130 reports of flooding, half a dozen structure fires, and several rescues of motorists stranded in vehicles.
Many drivers are avoiding driving through the rivers forming in the streets, while some residents are noticing that water is starting to seep through their front doors.
Authorities Advise People to Stay at Home
The winter storm is effecting nine states: California, Nevada, Arizona, Utah, New Mexico, Colorado, Idaho, Wyoming, and Montana. The storm’s impacts included a threat of hazardous conditions that could make traveling difficult.
“If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency,” the NWS office in Pocatello, Idaho, warned Newsweek.
Los Angeles Has Received 75 Percent of Its Normal Annual Rainfall
In the last two days, downtown Los Angeles received 7.03 inches of rain, according to AccuWeather. The city just witnessed its third wettest two-day span in history, with back-to-back days shattering daily rainfall records.
While Californians welcome the rain, the destructive storm is creating hazardous conditions by pushing mud, boulders, and debris down hillsides and roadways.
How Much Will This Storm Cost California?
Portions of Los Angeles County have accumulated more than 10 inches of rain since Sunday, with some areas reaching nearly one foot of rainfall, according to the National Weather Service. In the California mountains, heavy snowfall associated with atmospheric river-fueled storm systems has been packing the snow.
AccuWeather estimates that the storm and record rainfall in California will lead to $10 billion in damages and economic losses.
Atmospheric Rivers Are Common in West Coast Winters
Atmospheric rivers are a hallmark across the West Coast winter. Not all of these storms are harmful. Weaker atmospheric rivers offer the much-needed rainfall and snow that regions need. In these wet winters, the rainfall fills up water reservoirs before the dry, hot summers come.
Then, there are the more hazardous atmospheric rivers. Excessive rainfall increases the chances of flooding.
Not the West Coast’s First Atmospheric River
Unfortunately, this is not the first time the West Coast has faced an atmospheric river-fueled storm system. Between December 2022 and March 2023, heavy rainfall caused by multiple atmospheric rivers resulted in floods in parts of Southern California, the California Central Coast, Northern California, and Nevada.
Some areas were affected by flooding, mudslides, and power outages. Some areas received over 20 inches of rainfall, and at least 22 fatalities.
Atmospheric Rivers Happen All Over the World
While California has been battling atmospheric rivers for the last few years, these types of storms are not exclusive to the West Coast. They can also impact the eastern US and happen frequently in parts of Europe, Africa, Australia, and New Zealand.
Atmospheric rivers are fascinating weather phenomena. While they can be intense, the rain and snow are much needed during the winter months.
