Delays reported at major US airport as bomb cyclone brings high winds, flood threat to Northwest

Northern California is the bull's-eye of this atmospheric river. This has prompted the Weather Prediction Center to issue a rare "high" flash flood risk area for northern California for Thursday.

A powerful atmospheric river is slamming into Northern California and is expected to persist for days. Its effects, coupled with a bomb cyclone offshore, are being felt across the Pacific Northwest.

Strong winds at San Francisco International Airport on Wednesday are causing at least 30-minute arrival and departure delays, and the FAA says the number is expected to increase throughout the day as the storm rages. 

The bomb cyclone first began to slam the Seattle area Tuesday night, killing at least one person and injuring at least two others as 50-75 mph winds toppled trees across the region.

DEADLY BOMB CYCLONE SLAMS SEATTLE AREA WITH FIERCE WINDS LEAVING OVER 700,000 WITHOUT POWER

The worst is yet to come for Northern California, which is in the bull's-eye of this atmospheric river, according to the FOX Forecast Center. 

Through Saturday, some areas could see 3-5 inches of rain daily, with even higher amounts possible in the mountains. This has prompted the Weather Prediction Center to issue a rare "high" flash flood risk area for northern California for Thursday.

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The system is now bringing steady, moderate rain that will continue for several days, leading to potential flooding on roads, small streams and even larger rivers later in the week. 

According to the FOX Forecast Center, two storms are powering the event. The first is a powerful bomb cyclone. The strength of the low has kicked up strong winds up and down the coast, which have caused power outages and some damage.

Measurements showed the storm dropped 66 millibars (about 2 inches) in pressure in 24 hours, eventually becoming a storm with a central pressure of 943 millibars (27.85 inches) – on par with a major Category 4 hurricane.  It easily qualified for the title of "bomb cyclone," given when a storm's pressure drops about 24 millibars (about an inch) in 24 hours.

A High Wind Warning was issued for the Seattle and Everett areas on Tuesday night. This is the first such warning for the region since December 2022.

"The sound out here is unreal," resident Anthony Concannon said. "The wind in the trees and power lines is deafening."

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A tree falls onto a home in Issaquah, Washington, on Tuesday. (Eastside Fire & Rescue)

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A tree falls onto a home in Snohomish, Washington, on Tuesday. (Snohomish Regional Fire & Rescue)

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Two people were injured when a tree fell onto a trailer in Maple Valley, Washington, on Tuesday. (Puget Sound Fire)

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Two people were injured when a tree fell onto a trailer in Maple Valley, Washington, on Tuesday. (Puget Sound Fire)

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Two people were injured when a tree fell onto a trailer in Maple Valley, Washington, on Tuesday. (Puget Sound Fire)

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Wind damage seen in Mukilteo, Washington, on Tuesday.  (Mukilteo Fire Department)

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Wind damage seen in Mukilteo, Washington, on Tuesday. (Mukilteo Fire Department)

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Wind damage seen in North Seattle, Washington, on Tuesday. (Snohomish PUD)

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A tree falls onto a home in Issaquah, Washington, on Tuesday. (Eastside Fire & Rescue)

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A tree falls onto a home in Issaquah, Washington, on Tuesday. (Eastside Fire & Rescue)

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A tree falls onto a home in Issaquah, Washington, on Tuesday. (Eastside Fire & Rescue)

More than 700,000 people are estimated to have lost power across Western Washington as of early Wednesday morning, according to PowerOutage.US.  More than 100,000 of them were in the city of Seattle.

The winds were expected to abate by early Wednesday morning, allowing an extensive cleanup effort to begin.

In the Cascades, the winds have combined with heavy snow to produce life-threatening blizzard conditions. Travel over the passes is impossible Wednesday morning, which will slow down those commuting in the region. 

WHAT IS A BLIZZARD?

Like most atmospheric rivers, this one will dump feet of snow in the Cascades and the Sierra Nevada, according to the FOX Forecast Center. However, the warmer Pacific air being pulled in by strong winds will raise snow levels to higher than usual. 

Snow will likely begin around 3,500 feet, with the heaviest amounts above 4,000 feet, blanketing mountain ranges with several feet of snow.