Atmospheric river bringing heavy rain and snow to the Pacific Northwest this week

Two back-to-back storms were forecast to dump heavy snow and rain across parts of the Pacific Northwest, Northern California and the Rockies this week, prompting winter storm and flood warnings.

The storms that rip off the Pacific Ocean are the result of an atmospheric rivera corridor of air heavy with moisture that forms when warmer air from the tropics moves toward the poles.

As the first of the two storms moves inland on Monday, it will bring heavy coastal rain and snow to the highlands in the Pacific Northwest and Northern California. according to the National Weather Service. By evening and Tuesday, the wintry mix is ​​expected to spread across the northern Rockies and Great Basin, bringing as much as 8 to 12 inches of snow to the Cascades.

The next storm is expected to approach the Pacific Northwest Tuesday evening, bringing showers and thunderstorms along the coast and parts of the Coastal Ranges that have the potential to cause flooding. As the storm moves east, more snow could come to the Cascades.

“Total precipitation could reach 3 to 4 inches during the Olympics and up to 2 to 5 inches for Seattle and Portland,” said Elizabeth Danco, an Olympic meteorologist. AccuWeather.

The weather service office in Seattle warned residents about possible river flooding this week.

“There is little disruption between each system. As a result, several rivers are expected to reach the action stage, with minor flooding possible, especially by Wednesday or Thursday,” the outlook said. “The extent of flooding next week will depend on rainfall, temperature, snow levels and total rainfall in each of these weather systems.”

Winter storm warnings were active in several western states early Monday. In central Oregon, weather officials urged residents to remain cautious as they expect between 8 and 16 inches of snow and wind gusts up to 50 miles per hour.

“Traveling can be very difficult. The hazardous conditions could impact Monday morning and evening commutes. Gusty winds may cause tree limbs to fall,” the weather service in Medford, Oregon, wrote in a winter weather advisory that could be extended Tuesday. Similar warnings were issued in parts of Washington, Northern California, Utah and Nevada.

In the Northern Hemisphere, atmospheric rivers typically occur in winter, and in the West they are often mentioned for strong storms. According to NASA, these are the largest transport mechanisms of fresh water on Earth.

Storms threaten after record-breaking snow in Las Vegas and other cities

The atmospheric river approaching the northern west coast is expected to arrive as residents in some areas were still digging out record-breaking snowfall brought on by a winter storm last week.

Colorado, Lincoln and Elbert counties saw historic snowfall between Tuesday and Saturday, with the areas receiving 12 inches and 15 inches, respectively.

From Wednesday through Friday, New Mexico’s Colfax County was covered in 40 inches of snow, while parts of Albuquerque received 3 inches. New Mexico Governor Michelle Lujan Grisham declared a state of emergencywhich will release $1.5 million in state funding to support agencies responding to the winter storm.

More than 3 feet of snow fell in part of Las Vegas last week, breaking a decades-old record and causing road closures and power outages. The weather service office in Las Vegas warned Monday of strong wind gusts that could cause “damage to trees and power lines” and create “dangerous travel conditions.”

Contributions: John Bacon, Dinah Voyles Pulver.

This article originally appeared on USA TODAY: Storms threaten Seattle forecasts with heavy rain and snow in the Northwest