WeatherWatcher: Most damaging windstorm since December 14-15, 2006

 

City Light Outage Map for Shoreline 12:30am November 20, 2024

Around 30,000 City Light customers were without power in Shoreline and Lake Forest Park after midnight Wednesday morning. If you consider that each City Light customer likely serves more than one person on average, that likely covers most of the population. These widespread power outages were just short of a complete blackout.

As a region, over 600,000 electrical utility customers were without service at the peak of this event. This is the most number of power outages since the Hanukkah Eve windstorm of 2006. By wind speeds this storm wasn't nearly as big for Shoreline and Lake Forest Park. The unusual wind direction out of the east, in combination with some deciduous trees with foliage still left on them likely contributed to the widespread damage.

Wind gusts reached between 40-50mph in Shoreline and Lake Forest Park. The maximum gust measured was recorded at Central Market with a reading of 40mph at 7:13pm. My Richmond Beach station lost power shortly after 7:15pm and recorded a gust of 31mph just before going dark. 

I was doing maintenance on my Northridge weather station, and running various errands between 5:30pm and 6:45pm that took me from 145th street and Aurora Ave N, up to 205th street and 6th Ave NE. During that time I observed winds gusting out of the east between 20-45mph. There was also a tree down blocking the northbound right lane of Westminster Way N. However generally, I didn't observe any wind gusts that alarmed me, or any extra tree damage.

I then traveled north towards Everett, where I encountered violent winds on the freeway through Lynnwood at about 7pm. Gusts were knocking traffic in and out of their lanes within seconds, giving drivers no time to react. It was the first time in my many hours of severe weather driving that I've had my car get pushed sideways by a gust of wind. I would estimate those gusts were closer to 60-70mph.

The National Weather Service contradicted most other forecasts earlier Tuesday and downplayed the wind threat for the Seattle metro area as wind advisory criteria, forecasting gusts up to 45mph. At 8:03pm Tuesday night the National Weather Service upgraded the advisory to a high wind warning, noting gusts to 65mph were likely. A little too late for many as much of the damage had already occurred.

A large Douglas Fir falls on to Pam's house.
Photo by Pam Cross

Regionally, for weather stations that retained power and data logging abilities, there were gusts in the Puget Sound lowlands recorded as high as 74mph. Seatac had a gust of 59mph, Paine Field in Everett had a maximum wind gust of 48mph at 7:56pm. 

Bomb cyclones: Also known as Explosive cyclogenesis, is not a new term, but has become a very popular term in recent years. The Pacific Northwest is no stranger to Pacific cyclones or bomb cyclones, as many develop off our west coast each year. Most stay too far offshore or weaken before they get close enough to have any significant impacts on our region. Typically, they are far north of us, or south of us, and bring the usual fall and winter rainstorms with them.

Tuesday's cyclone stayed about 300 miles off the west coast. A combination of this particular storm becoming strong, high pressure lining up just east of the Cascade Mountain range, and its proximity to our west coast, was what resulted in our unusually strong easterly winds. Impacts could have been far worse had this storm made landfall.

The next cyclone: We have another storm expected to rapidly develop off our west coast on Friday. This storm is not expected to become as strong, but it is expected to get closer. Some forecasts have the storm on a track to make landfall on Vancouver Island.

There is potential that this one could make a wind event, particularly over the northern half of Puget Sound, which could include Shoreline and Lake Forest Park. The forecast is calling for breezy or windy conditions Friday afternoon, with gusts to 30mph out of the southwest. There are no watches, warnings or advisories from the National Weather Service at this time, but that could change.

For current weather conditions please visit www.shorelineweather.com