On December 12, 1969, a category F3 tornado forms over Puget Sound and comes ashore north of Saltwater State Park. Moving northeast, the twister passes over Des Moines and strikes the community of Midway, then crosses Interstate 5 and travels through the western part of Kent. Trees are uprooted and buildings and vehicles are damaged or destroyed, but the only significant injury is a broken leg sustained by a 9-year-old boy. The twister is an outlier in a state that normally averages two or three weak tornadoes a year, usually in the eastern part of the state. As of 2022, it remains the only F3 tornado recorded in King County.
Chance of Thunderstorms
It was supposed to be winding down. An especially strong storm had passed through Western Washington the day before, with 60 mph wind gusts which ripped nine sheets of aluminum siding off the new 50-story Seafirst building in downtown Seattle. But Friday, December 12, was supposed to be calmer, with a chance of thunderstorms and wind gusts to 30 mph forecast.
When a thunderstorm formed over central Puget Sound that afternoon, it initially attracted little attention. Then people near the waterfront in Redondo saw a large waterspout over the water. At about 2:25 p.m., the tornado came ashore just north of Saltwater State Park in the little community of Zenith and passed over Des Moines. Traveling northeast, the tempest did relatively little damage until it approached the intersection of Highway 99 and the Kent-Des Moines Road, which then was part of the Midway community. Here, a number of homes and businesses were damaged or destroyed, trees were uprooted, signs demolished, and at least one car flipped over. Vehicles at nearby Highline Community College were damaged both by falling trees and by the abrupt change in air pressure as the storm passed, which caused windows in several cars to shatter.
On Interstate 5 just east of Midway, amazed drivers slowed down and watched the tornado's approach. Some were so distracted they bumped into cars in front of them. Others wisely pulled off the freeway. The storm passed directly over 1-5, ripping a camper unit from a pickup truck and blowing both the truck and a small car off the road. The twister then crossed the Green River and briefly jogged north near the waterway. This area, in the western outskirts of Kent between S 228th and S 212th streets and east to approximately the West Valley Highway, also sustained significant damage. The most serious injury occurred here, when 9-year-old David Archey suffered a broken leg when he was struck by a collapsing shed near his home on Russell Road.
The tornado swung back toward the northeast and sailed through a parking lot at the Boeing Space Center, located on the West Valley Highway between S 199th and S 212th streets, damaging vehicles and buildings alike. South of the center, a house was lifted off its foundation and turned nearly 90 degrees before it dropped back down. "But the funny thing was what it (the tornado) didn't do," explained one of the residents, identified by The Seattle Times as Mrs. Harold Pierce. "Pictures are hanging on the walls, just as straight as if nothing had ever happened. The clock and other things are still on the walls, like normal. Big, strong things are busted. Fragile things aren't" ("Moments Left ...").
The storm then retreated skyward. There was an unconfirmed sighting of the tornado farther east near Lake Youngs, but the worst was over. There were initial reports of an additional one or two tornadoes which were said to have quickly disappeared. This phenomenon was explained by Wallace Donaldson, chief meteorologist at the Sea-Tac Airport weather office, who watched the tornado as it passed south of the airport. He reported that it first appeared as a single funnel and vortex, then momentarily split into two separate funnels and vortexes before rejoining into one. It was subsequently classified as a single tornado and rated as an F3 on the Fujita Tornado Damage Scale, defined as having winds of 158-206 mph. To date the tornado remains the only F3 tornado recorded in King County, and just the third in Washington.