Hanukkah Eve windstorm of 2006 off the Washington Coast on December 15, 2006, at 2:00 UTC.

Pacific Northwest windstorms, sometimes colloquially known as Big Blows,[1] are extratropical cyclones which form in the Pacific basin, and affect land areas in the Pacific Northwest of the United States and British Columbia, Canada. They form as cyclonic windstorms associated with areas of low atmospheric pressure that track across the North Pacific Ocean towards western North America. Deep low pressure areas are relatively common over the North Pacific. They are most common in the winter months. On average, the month when most windstorms form is November or December.

The closest analogue to these storms are European windstorms, which develop over the eastern portion of the North Atlantic Ocean as opposed to the North Pacific.[2] Nor'easters, a similar class of extratropical cyclones, commonly affect the east coast of North America. While the storms on the East Coast are named "nor'easters", the Pacific Northwest windstorms are not called "nor'westers" because the cyclones' primary winds can blow from any direction, while the primary winds in nor'easters usually blow from the northeast.[3]

Categories and frequency

Storm tracks of the central low pressure of the storms which hit the Pacific Northwest in 1962, 1981 and 1995
Office of Washington State Climatologist Windstorm Categories[4]
Average Peak Instant Gust (mph) Windstorm Category Approximate Return Interval
39-44 Minor Several per year
45-54 Moderate Annual
55-64 Major Once every 20–30 years
65-74 Extreme Once every 50–100 years
75+ Phenomenal Once every 250–500 years

Notable Pacific Northwest windstorms

See also


  1. ^ Knox, John A.; Frye, John D.; Durkee, Joshua D.; Fuhrmann, Christopher M. (2011). "Non-Convective High Winds Associated with Extratropical Cyclones". Geography Compass. 5 (2): 63–89. doi:10.1111/j.1749-8198.2010.00395.x. Retrieved April 16, 2013.
  2. ^ Mass, Clifford; Dotson, Brigid (2010). "Major Extratropical Cyclones of the Northwest United States: Historical Review, Climatology, and Synoptic Environment". Monthly Weather Review. 138 (7): 2499–2527. Bibcode:2010MWRv..138.2499M. doi:10.1175/2010MWR3213.1. S2CID 19410610.
  3. ^ Nic Loyd; Linda Weiford (November 4, 2021). "Weathercatch: The Northeast had a Nor'easter, why wasn't our storm a Nor'wester?". The Spokesman-Review. Retrieved November 4, 2021.
  4. ^ "Some Historical Weather Events in the Pacific Northwest". Office of Washington State Climatologist. Retrieved April 15, 2013.
  5. ^ Read, Wolf. "Two Windstorms in Three Days November 13–15, 1981". The Storm King, hosted by the Office of Washington State Climatologist. Retrieved April 17, 2013.
  6. ^ "Wind Storms". Office of Emergency Management, Seattle. Retrieved April 15, 2013.
  7. ^ "Washington's Top 10 Weather Events of 1900s". National Weather Service, Portland Oregon. Retrieved April 17, 2013.
  8. ^ Read, Wolf. "The Major West Coast Windstorm of December 12, 1995". The Storm King, hosted by the Office of Washington State Climatologist. Retrieved April 14, 2013.
  9. ^ Read, Wolf. "December 14-15, 2006 Windstorm". The Storm King, hosted by the Office of Washington State Climatologist. Retrieved April 14, 2013.
  10. ^ Pawson, Chad (August 29, 2015). "B.C. Lower Mainland storm cuts power to 400,000 homes". CBC News. Retrieved October 14, 2017.
  11. ^ "B.C. storm: 'Largest outage event' in BC Hydro history". CBC News. September 1, 2015. Retrieved October 14, 2017.
  12. ^ "The mid-October windstorm in the Pacific Northwest | NOAA Climate.gov". www.climate.gov. October 28, 2016. Retrieved November 1, 2016.
  13. ^ "December storm 'most damaging' in BC Hydro's history, report says". CBC News. January 2, 2019. Retrieved June 29, 2019.
  14. ^ "In pictures: Powerful December windstorm blasts B.C.'s south coast | Globalnews.ca". globalnews.ca. December 20, 2018. Retrieved February 24, 2019.
  15. ^ "Extratropical Cyclones Drench West Coast". earthobservatory.nasa.gov. October 25, 2021. Retrieved October 28, 2021.