A powerful winter storm brewing near the Pacific Northwest is forecast to bring damaging gusts, feet of mountain snow and heavy rain to parts of California, Oregon and Washington that could trigger flooding, mudslides and rock slides in the region.
The storm, known as a “bomb cyclone,” is dragging an atmospheric river along with it, a plume of moisture-filled air that “will act like a massive firehose of rain at low elevations and a giant snow gun over the high country,” AccuWeather reported. The rapidly intensifying storm is expected to soak the region at least through Friday and into the weekend in some areas, according to The Weather Channel.
“It’s definitely our first significant storm. I would say depending on how you want to define winter, I suppose you could call it the first winter storm,” Sara Purdue, a National Weather Service meteorologist, told the Redding Record Searchlight, part of the USA TODAY Network, Monday.
The bomb cyclone comes as powerful storms are expected to bring heavy snow and gusty winds to the Great Lakes, central Appalachians, the Northeast while rain and flash flooding is forecast for the Gulf Coast.
NOAA’s Weather Prediction Center issued a rare high risk excessive rainfall outlook for northwest California Thursday due to the serious threat of flooding. The heaviest rainfall will move from Northern California into southwest Oregon, drenching some areas in up to 15 inches of rain, then northward through western Oregon and Washington, according to the Weather Channel. Areas recently affected by wildfires and mountain roads could be vulnerable to mudslides and rockslides, the outlet warned.
More: Winter could bring blizzards, nor’easters, bomb cyclones: What to know
A snow plow passes a chaining area along Highway 58 during a snow storm Monday, Nov. 18, 2024.
The National Weather Service has also issued winter weather alerts and a blizzard warning from the Washington Cascades to California’s northern Sierra as snow levels are expected to rise throughout the week, The Weather Channel reported. The blizzard conditions combined with low-elevation flooding in the mountains are expected to cause widespread impacts to travel, according to AccuWeather.
Meteorologists predicted coastal regions of Northern California, Oregon and Washington may also see gusts of up to 70 mph later Tuesday and early Wednesday that could down trees and knock out power.
“Numerous flash floods, hazardous travel, power outages, and tree damage can be expected as the storm reaches max intensity,” on Wednesday, the Weather Prediction Center said on X.
Snow, tornadoes, storms: Wild weather extremes will make for an active week
Travel will be ‘near impossible’ in the mountains
Heavy, wet snow is expected to accumulate in many of the Pacific Northwest’s mountain ranges, resulting in “whiteout conditions and near impossible travel, especially at pass level in the Cascades and northern California,” the weather service’s Weather Prediction Center said on X.
Wind gusts as high as 50 mph and between 12 and 24 inches of snow will hit elevations higher than 3,000 feet in the Olympics, including the cities of Grisdale, Hurricane Ridge, Quinault, Mount Olympus, and Amanda Park, according to the weather service in Seattle. Forecasters urged travelers to slow down and use caution.
Heavy snow could also make travel difficult in portions of southern Trinity, to the east of Forest Glen and Hyampom, and above around 3,500 feet, including sections of Highway 36, according to forecasters in Eureka, California.
Chris Woodward, spokesman for the California Department of Transportation, told the Record Searchlight chain controls are expected to be in place at the higher elevations of Interstate 5 in Northern California.
“The most important thing motorists need to know is to be prepared, have those chains when you need to have them,” Woodward said.
Caltrans recommends drivers check their brakes, battery, windshield wipers, defroster, heater, headlights and exhaust system before traveling in the mountains, the Record Searchlight reported.
In addition to packing chains, Woodward told the outlet drivers should have an ice scraper and shovel, flashlight, warm blankets, water, non-perishable food items and a cell phone.
Rain, wind and floods across the nation
The weather service said early Tuesday there will be “no shortage of active weather across the Nation.”
A potent storm system will produce strong winds up to 65 mph and heavy snow across Nebraska, eastern Montana, and the Dakotas through Wednesday. Rain will hit the Midwest, Great Lakes and Mid-Atlantic Tuesday as well as the central Appalachians and Northeast through the end of the week, including up to a foot of snowfall in parts of West Virginia and western Maryland.
Eastern Louisiana and the western Florida Panhandle are facing the risk of flash floods as thunderstorms bring heavy rain through the night.
What is a bomb cyclone?
A bomb cyclone – a potent cold-season coastal storm that’s so-named due to its explosive strength – is colloquially known as a winter hurricane.
Such storms undergo an intensification process known as bombogenesis, which is a quick drop in atmospheric pressure, marking the strengthening of the storm, according to the National Oceanic and Atmospheric Administration (NOAA).
Bombogenesis is said to occur when a storm’s central barometric pressure drops at least 24 millibars in 24 hours. A millibar is a way of measuring pressure. The lower the pressure, the more powerful the storm.
Some of the most intense winter storms to batter the country’s coasts have been bomb cyclones.
The word “bombogenesis” is a combination of cyclogenesis, which describes the formation of a cyclone or storm, and bomb, which is pretty self-explanatory.
“This can happen when a cold air mass collides with a warm air mass, such as air over warm ocean waters,” NOAA said. “The formation of this rapidly strengthening weather system is a process called bombogenesis, which creates what is known as a bomb cyclone.”
In the 1940s, some meteorologists began informally calling some big coastal storms “bombs” because they develop “with a ferocity we rarely, if ever, see over land,” said Fred Sanders, a retired MIT professor who brought the term into common usage by describing such storms in an article in the journal Monthly Weather Review in 1980.
Bomb cyclones are powerful winter storms Here’s a visual breakdown of how they’re created.
What is an atmospheric river?
Sometimes called “rivers in the sky,” atmospheric rivers are a major factor in extreme rain and snowfall in the West.
Atmospheric rivers function much like rivers on the surface but can carry even more water than the mighty Mississippi River. The water can travel for thousands of miles.
They’re responsible for more than 90% of the water vapor transported to the mid latitudes from the tropics, according to a blog Kai-Chih Tseng wrote for the National Oceanic and Atmospheric Administration. Atmospheric rivers occur around the world but occur most often along storm tracks near jet streams, Tseng wrote.
When studying atmospheric rivers, scientists look at systems more than 1,000 miles long, less than 620 miles wide and an average of 1.8 miles in depth. Studies show they typically last around 20 hours in an area over the coast.
Contributing: Janet Loehrke, Ramon Padilla, Dinah Voyles Pulver, USA TODAY; David Benda, Redding Record Searchlight
This article originally appeared on USA TODAY: Bomb cyclone to bring snow, more issues to the Pacific Northwest
