A severe winter storm brewing near the Pacific Northwest is forecast to bring damaging wind gusts, feet of mountains snow and heavy rain to parts of California, Oregon and Washington that could trigger flooding, mudslides and landslides in the region.

The storm, known as a “bomb cyclone,” is bringing with it an atmospheric river, a plume of moisture-laden air that “will act as a massive firehose of low-elevation rain and a giant snow cannon over the high country,” AccuWeather reported. The rapidly intensifying storm is expected to drench the region at least through Friday and into the weekend in some areas, according to The weather channel.

NOAA’s Weather Prediction Center issued a rare high risk of heavy precipitation for Northwest California Thursday due to the severe threat of flooding. The heaviest rainfall will move from northern California to southwestern Oregon, drenching some areas in up to 15 inches of rain, then north through western Oregon and Washington, according to the Weather Channel. Areas recently affected forest fires and mountain roads may be susceptible to mudslides and rock slides, the outlet warned.

More: Winter can bring blizzards, nor’easters, bomb cyclones: What you should know

The National Weather Service has also issued winter weather warnings 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 flooding at low elevations in the mountains are expected to cause widespread travel impacts, according to AccuWeather.

Meteorologists predicted coastal areas of northern California, Oregon and Washington could also see wind gusts of up to 70 mph later Tuesday and early Wednesday that could down trees and knock out power.

“Much flooding, hazardous travel, power outages and tree damage can be expected as the storm reaches maximum intensity,” the Weather Prediction Center said Wednesday. X.

Snow, tornadoes, storms: Wild weather extremes will make for an active week

Travel will be “almost 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, particularly 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 towns of Grisdale, Hurricane Ridge, Quinault, Mount Olympus and Amanda Park, according to weather service in seattle. Forecasters urged travelers to slow down and use caution.

Heavy snow could also make travel difficult in parts of southern Trinity, east of Forest Glen and Hyampom, and above about 3,500 feet, including parts of Highway 36, according to forecaster in Eureka, California.

“If you must travel, keep an extra flashlight, food and water in your vehicle in case of an emergency,” the weather service said.

What is a bomb cyclone?

A bomb cyclone – a potent cold-season coastal storm so called because of its explosive power – is colloquially known as a winter hurricane.

Such storms undergo an intensification process called bombogenesiswhich is a rapid drop in atmospheric pressure, marking the strengthening of the storm, according to the National Oceanic and Atmospheric Administration (NOAA).

Bombogenesis said to occur when a storm’s central barometric pressure drops by at least 24 millibars in 24 hours. A millibar is a way of measuring pressure. The lower the pressure, the stronger the storm.

Some of the most intense winter storms to hit 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 called a bomb cyclone.”

In the 1940s, some meteorologists began informally calling some large coastal storms “bombs” because they develop “with a ferocity that we rarely, if ever, see over land,” said Fred Sanders, a retired MIT professor who brought the term into common use of describing such storms in an article in the journal Monthly Weather Review in 1980.

Bomb cyclones are severe winter storms Here is a visual breakdown of how they are created.

What is an atmospheric river?

Sometimes called “rivers in the sky”, atmospheric rivers is a major factor in extreme rain and snowfall in the West.

Atmospheric rivers act much like surface rivers but can carry even more water than the mighty Mississippi River. The water can travel thousands of miles.

They are responsible for more than 90% of the water vapor transported to the mid-latitudes from the tropics, according to a blog written by Kai-Chih Tseng for the National Oceanic and Atmospheric Administration. Atmospheric rivers occur around the world but most often occur along storm tracks near jet streams, Tseng wrote.

When studying atmospheric rivers, scientists look at systems that are more than 1,000 miles long, less than 620 miles wide and an average of 1.8 miles deep. Studies show that they usually last around 20 hours in an area over the coast.

Contributes: Janet LoehrkeRamon PadillaDinah Voyle’s PowderUSA TODAY

This article was originally published on USA TODAY: Bomb cyclone to bring snow, more trouble to Pacific Northwest