SEATTLE — The effects of a rapidly developing “bomb cyclone” slammed the Seattle area Tuesday night, killing at least one person and injuring two others as 50-75 mph winds toppled trees across the region.

A woman was killed in Lynnwood when a tree fell into an encampment, according to South County Fire officials.  

South of Seattle, two others were injured when a tree fell into their trailer in Maple Valley, reported Puget Sound Fire. 

One person was freed quickly, but it took firefighters an hour to free the other resident who was trapped in the mangled debris. Both were taken to local hospitals, but their conditions were not given.

A driver was struck by a falling tree as they were driving in northeastern Seattle, according to the Seattle Fire Department. That person was freed and listed in stable condition, firefighters said. Crews there said multiple other trees toppled near the intersection.

Wind gusts in the Cascade foothills just east of Seattle reached over 70 mph, fueled by a low pressure center that underwent explosive development in just hours as it swirled off the Washington coast.

An estimated more than 600,000 people had lost power across Western Washington as of 11 p.m. PT, according to PowerOutage.US.  Over 110,000 of them were in the city of Seattle.

A wind gust reached 74 mph in the town of Enumclaw before the wind gauge went dark, along with the rest of the town.

“The sound out here is unreal!” said Anthony Concannon. “The wind in the trees and power lines is deafening.”

In Bellevue, the state’s 5th-most populous city, gusts of 52 mph sent firefighters scrambling to assist multiple neighborhoods reporting trees into homes.

“Trees are coming down all over the city & falling onto homes,” Bellevue Fire officials said. “If you can, go to the lowest floor and stay away from windows. Do not go outside if you can avoid it.”

State and local city departments said multiple main highways were blocked by falling trees and power lines, including stretches of busy State Routes 18, 516 and 169. Just before midnight, a tree fell across 4 lanes of Interstate 405 in Bellevue.

“There are so many trees and power lines down, we would be posting the locations till the lights turn on,” an exasperated Snohomish Regional Fire & Rescue posted on X.

Easterly gusts reached 59 mph at Sea-Tac Airport, where the rare east winds brought pilots a challenging crosswind to navigate runways aligned for the persistent southerly winds the region normally endures.

Bomb cyclone drops 66 millibars of pressure in 24 hours

The storm was brought about by a historic storm that went from an innocuous low pressure trough to tying the strongest storm ever recorded in that part of the Pacific Ocean. Measurements showed the storm dropped 66 millibars in pressure in 24 hours, eventually becoming a storm with a central pressure of 943 millibars – on par with a major Category 4 hurricane.  It easily qualified for the title of “bomb cyclone”, given when a storm strengthens about 24 millibars in 24 hours.

While the deep center of the storm remained hundreds of miles offshore, the alignment of the storm due west of the Washington Coast combined with cold, dense higher pressure in eastern Washington created a tremendous difference in pressure across the western half of the state.

Wind from eastern Washington slammed into the barrier created by the Cascade Mountains, but gaps in the terrain along the mountain passes created breaks in the barrier, allowing winds to accelerate and shoot through the passes like a hole in a balloon.

The winds pummeled towns nestled along the foothills that sit along the highways providing gateways to the popular hiking trails and ski resorts.

As the east winds reached the western edges of the Cascades and broke free of their mountain captors, they raced across the Puget Sound lowlands, bringing rare easterly winds that caught off guard the forested landscapes steeled to the more common southerly winds of the region. The result was widespread tree falls from north to south along the Puget Sound region.

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