The phenomenon o Extremely strong west or northwesterly winds will surge through the Strait of Juan de Fuca, with the greatest speeds occurring near the eastern mouth of the Strait. A high amplitude upper level ridge extending into Alaska and a shortwave trough over southwest BC causes upper level westerly winds over the Strait. A strong pressure gradient from the western to eastern mouth of the Strait causes westerly winds at the surface.

The result o Falling trees o Huge power outages o Dangerous seas o Extensive property damage o Loss of life

December 17, 1990 – The Elwha Storm o Winds gusting over 60 mph from Edmonds to Whidbey Island o Several fallen trees damaged cars and homes o The ferry Elwha sustained $3 million in damage after being repeatedly slammed against the pier at the Port of Everett. The pier was also badly damaged. o 25,000 homes lost power o Local marinas sustained millions of dollars in damage

December 17, 1990 Seattle Times and The Snohomish County Daily Herald

December 17, 1990 ◄ NCEP 500 hPa reanalysis at 06Z on Dec 18. A high amplitude ridge extends into Alaska and a shortwave trough passes over southwest BC causing upper level westerly winds. ► Surface observation chart at 02Z on Dec 18 (during the hour of maximum winds). Smith Island is recording a 39 knot wind. A pressure difference of 4.6 hPa can be seen between the west entrance of the Strait and Smith Island.

December 17, 1990

…and when you have a ferry graphic, why not use it…

October 28, 2003 – The Ivar’s Storm o Strong winds surged eastward through the Strait behind a strong Pacific front, producing wind gusts exceeding 60 mph from Edmonds to Whidbey Island. o Nearly 100,000 people lost power o One death on Whidbey Island from a tree falling onto a parked car o Partial destruction of Ivar’s restaurant at Mukilteo Landing

October 28, 2003 Seattle Times

Ivar’s “rogue wave” mural …and the carp…

October 28, mb heights overlaying an infrared satellite image from 4 PM PST on Oct. 28. A high amplitude ridge extends into Alaska and a short wave trough over southwest British Columbia causes upper level westerly winds in the Strait. NCEP surface pressure reanalysis at 4 PM PST on Oct. 28. A 4-5 mb pressure difference from the western mouth to the eastern mouth of the Strait, causing a westerly wind at the surface.

October 28, 2003 The MM5 predicted winds near 40 knots (20 m/s) at the eastern mouth of the Strait 24 hours in advance of the storm.

October 28, 2003

Stations Paine Field – KPAE Point Wilson – K53S Race Rocks – CWQK Smith Is. – SISW1 Whidbey Is. – KNUW

Climatology – How often? o Examine data from these stations. o Consider winds in the direction of 250° to 300° and exceeding 30 knots. o Count the number of days in which this occurred over a 10 year period. o How do the different stations compare? o Do we need to modify our parameters? o Do we have any problems with our data? o Which station(s) are a good gauge?

Answers? Station IDs Wind Speed (knots)Smith Is. # of DaysRace Rocks # of DaysWhidbey # of DaysPaine Field # of Days total January 1994 – December 2003 UCAR 30+ knots 250° - 300°

Answers… o The different stations show varying numbers of days This could be due to using the same parameters on stations that are in very different places o The data sets for some of these stations are incomplete. We are working to fill those time gaps with our own archived data. o Smith Island appears to be a good gauge due to its location and data quality.

What’s next? o Organize a list of several dates where high winds were observed at multiple stations o Look at synoptic patterns and categorize storms o Run composites on similar storms o Dissect our case studies, rerun models o We want to know how many different ways these high winds can occur, what causes them. o Which stations miss out and why? o Publish our results

Acknowledgments o UW Department of Atmospheric Sciences o Professor Cliff Mass o NOAA/NWS o Neal Johnson o UCAR/NCAR o NDBC o NCDC Contact information: