Forecasters have released new maps showing impacts of the ‘bomb cyclone’ moving toward the West Coast, revealing which states will endure hurricane-like conditions.
The National Weather Service (NWS) alerted residents in northern California, Oregon and Washington to potential hurricane-force winds, catastrophic flooding and feet of high-elevation snowfall starting Tuesday afternoon.
The bomb cyclone, essentially a giant spinning vacuum in the atmosphere, is expected to pull a Category 5 atmospheric river onto land that ‘will act like a massive firehose of rain at low elevations and a giant snow gun over the high country.’
A wind projection map showed gusts between 60 to 70 miles per hour from Eureka to Coos Bay and up the coast north of Aberdeen.
Places like Oregon’s Klamath Falls, Bend and Penleton and Seattle in Washington can expected between 50- to 60-mile-per-hour winds.
A precipitation map projected rainfall could reach up to five inches in north-central and northwestern California, western Oregon and western Washington, and northeastern California may see up to 20 inches.
Meteorologist Ryan Maue said on X that the ‘mega’ bomb cyclone and ‘climate fueled’ atmospheric river will dump trillions of gallons of rain over the Northwest this week, totaling almost 20 trillion gallons.
A map created by Weatherbell.com shows which areas will endure the most precipitation from a bomb cyclone and atmospheric river that will impact the West Coast
Powerful gusts could trigger power outages in all three affected states, especially in areas under a high-wind warning.
From Tuesday night to Wednesday, the atmospheric river will be mainly directed at the southwestern Oregon and Northern California coasts, according to AccuWeather.
AccuWeather Senior Meteorologist Heather Zehr said: ‘Soaking rain from the storm will reach the San Francisco Bay area but not until later in the week.
‘The heaviest rain will fall near and north of the North Bay and up along the coast of Northern California while San Francisco and the South Bay will be in the zone where rainfall will diminish quickly from north to south.’
While California, Oregon and Washington will be the only states directly impacted by this double-system weather event, storm conditions could stretch beyond their borders.
Idaho is expected to see three to four inches of total rainfall this week, and areas as far East as Kansas and as far south as the California-Mexico border could receive up to an inch.
The heavy precipitation will move into the West Coast Tuesday afternoon, accompanied by high winds as the bomb cyclone and atmospheric river approach land, Washington Post forecaster Ian Livingston reported.
Current forecasts place the focus of storm conditions from Vancouver Island in Canada to around the Oregon-California border on Tuesday night.
A wind projection map showed gusts between 60 to 70 miles per hour from Eureka to Coos Bay and up the coast north of Aberdeen. Places like Oregon’s Klamath Falls, Bend and Penleton and Seattle in Washington can expected between 50- to 60-mile-per-hour winds
The National Weather Service (NWS) alerted residents in northern California , Oregon and Washington to potential hurricane-force winds, catastrophic flooding and feet of high-elevation snowfall starting Tuesday afternoon
‘Heading into Wednesday, the atmospheric river will probably shift its focus slowly southward from southern Oregon into Northern California,’ Livingston reported.
Toward the end of the week and into the weekend, rain and high-elevation snow could shift toward central or Southern California, he added.
The storms are also set to bring heavy snow to the region, with several inches to a foot over the passes in the Cascades.
Bomb cyclones form when a midlatitude storm rapidly intensifies over a 24 hour period.
Intensification essentially means a drop in pressure, and storms need to drop at least 24 millibars within a 24-hour period to be considered a bomb cyclone.
Maue said that the central pressure of this bomb cyclone will fall almost 70 millibars in 24 hours, reaching pressure levels similar to that of a Category 4 hurricane.
It is rare for a storm to lose 70 millibars of pressure this quickly.
By comparison, Hurricane Milton – which rapidly strengthened from a Category 1 hurricane to a Category 5 – lost 84 millibars of pressure in 24 hours.
The bomb cyclone will also direct a Category 5 atmospheric river toward the West Coast, which is a long and narrow region of the atmosphere that carries warmth and moisture from the tropics toward Earth’s poles.
A Category 5 is exceptionally hazardous, bringing intense storm impacts to land.
As these storm systems move inland, areas affected by burn scars, or charred, barren patches of land left behind by wildfire, will be especially prone to flooding.
That is because burned soil can be as water-repellant as pavement, according to the National Oceanic and Atmospheric Administration (NOAA).
Mudslides and rockslides are also more likely in areas recently impacted by wildfire, as the loss of trees, vegetation and their roots leaves soils unstable and easily-erodible.
