Windstorm 2021: More similar than different from the historic storm of 2015

The memories of the historic Inland Northwest Windstorm of 2015 are still fresh for many of us.  Ponderosa Pine stumps still dot my neighborhood from the fallen trees. Every time the power goes out, I remember my week with no electricity.  It was a 100-year storm, but just over five years later, Wednesday’s event felt amazing similar.

Similar Windstorms  Peak wind gusts 2021

Peak wind gusts

Windstorm 2021 matched 2015’s fury on many fronts.  The peak wind gust reported at Spokane International Airport was 71 mph in both storms!  One thing of note, the power was knocked out to the airport during part of the time that the winds were at their peak in 2015.  It is conceivable that we could have had a stronger gust.  For comparison, Fairchild Airforce Base reported a peak wind gust of 71 mph in 2015, and a 61 mph gust Wednesday morning.

Duration of the strongest winds

The major difference between the two storms is the duration of the strongest winds.  Once wind gusts reach 60 mph+, Ponderosa Pine trees start falling fast.  In 2015 those peak winds lasted more than 6 hours at Fairchild Airforce Base.  Wednesday morning’s highest gusts occurred right around the cold front as it passed, and they lasted just over 2 hours.

Area of destruction

Meanwhile, the area hardest hit by these two storms was very similar.  Spokane and Coeur d’Alene were in the bullseye of the strongest winds, which extended down into Pullman.

Familiar storm pattern

Finally, the track of the two windstorms was very similar. The big wind events in the Inland Northwest typically occur when strong low pressure deepens as it tracks across southern British Columbia, and continues deepening as it crosses the Continental Divide.  “Both storms had fast moving lows that are quickly followed by high pressure building behind them. The gradient between the departing low and the incoming high can really increase the surface pressure gradient across the Cascades,” said National Weather Service meteorologist Greg Koch.

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Questions yet to be answered

Early numbers indicate that the number of power outages was around 100-thousand on Wednesday.  During the 2015, at least 206-thousand customers in the Inland Northwest were without power.  Some were in the dark for more than week.  Once the damage is assessed, that will give a more complete comparison of these similar storms.  Hopefully Windstorm 2021 will pale in that comparison.