11 years after the strongest summer windstorm on record, a new system heads for western WA

On Saturday, Aug. 29, 2015, the strongest summer windstorm on record swept through western Washington.

Wind gusts of up to 70 mph pounded the Whidbey Island Naval Air Station, and Everett-Paine Field had wind gusts topping 60 mph. The Seattle-Tacoma International Airport (SEA) peak winds reached nearly 50 mph, while at the Olympia and Bremerton airports, the strongest winds topped 45 mph.

With leaves on trees, branches were more easily ripped away, and some trees fell onto homes, roads, and more.

Over a half million customers lost power in the midday Saturday storm. It took days for power crews to return power service to customers.

Two people lost their lives due to fallen trees and large branches. Many roads were blocked by downed trees, including I-405 just south of I-5 in Lynnwood and Bothell.

No other windstorm has ever occurred like this one in summer. This storm was one that would occur in the fall or winter season, not during summer. With leaves on trees acting as sails on a ship, the strong winds more easily toppled trees and knocked down tree branches.

The windstorm was well forecast in advance, yet being an August weekend, many people were not paying much attention to the weather. In fact, that Saturday morning had sunshine as the storm approached, tending to give the impression of a nice day ahead.

But by midday, the windstorm struck. Some boaters on waterways including Puget Sound were caught unaware, with several capsizes and rescues.

No windstorm this weekend, but rain is on the way

No such strong winds like those of 11 years ago are forecast for this weekend, though a change in the dry August weather pattern is underway.

A weakening Pacific weather system moving onshore by Saturday morning from the Gulf of Alaska is expected to bring some spotty light showers. Winds associated with this system are anticipated to be no stronger than 10 to 20 mph from the south.

A following weather system is forecast to arrive Tuesday night into Wednesday of next week, offering an even better chance for a more meaningful and widespread rainfall. Rain amounts with this system could reach as much as a quarter inch.

High temperatures this weekend and into next week are expected to be close to seasonal averages, ranging from the mid-60s to the lower 70s.

A silver lining – this period of cooler weather with winds blowing inland from the Pacific Ocean means wildfire smoke from British Columbia and Eastern Washington should remain out of Western Washington for good air quality.

The Aug. 29, 2015, windstorm was quite unusual and remarkable, yet it could happen again. It is always important to be weather-aware and, as a result, weather-prepared.

Ted Buehner is the KIRO Newsradio meteorologist. Follow him on X and Bluesky. Read more of his stories here.