March 12–13th, "Bora" Windstorm across much of South-Central Alaska
Carven A. Scott, NOAA/NWSFO, Anchorage, AK; and S. E. Baines and J. P. Papineau
A record breaking wind storm struck the Susitna and Matanuska Valleys, the Anchorage Municipality, portions of the Kenai Peninsula and Prince William Sound on Wednesday and Thursday, March 12 and 13, 2003. What made this windstorm especially interesting was that it was a “Bora”, or cold-advection windstorm as opposed to the more common downslope, “Chinook” windstorm.
An unseasonably strong high latitude blocking pattern set up across North Central Alaska late in the first week of March. The block proceeded to retrogress west during the second week of March, and a vigorous short wave trough on the west side of the Hudson Bay Vortex drove south across Alaska. The westward movement of this upper ridge allowed the “blocked” low-level arctic air to phase with the strong cold advection aloft to produce the damaging winds across South Central Alaska.
The Ted Stevens International Airport tower experienced record wind speeds around midnight Thursday, with sustained winds of 80 to 82 kt (92 mph to 94 mph), and a peak wind gust of 95 kt (109 mph). The tower was abandoned and the airport was shut down for several hours during the early morning hours of Thursday. Peak winds of 73 kt to 86 kt (84 mph to 100 mph) were reported from the Matanuska Valley (north of Anchorage) to Valdez on Prince William Sound. Ambient air temperatures during the event were around 0F (-17C).
Damage from the wind event exceeded $3.5 Million in Anchorage alone with almost $4.5 Million reported in the Matanuska Valley. Total damage from the storm across South Central Alaska exceeded $5 Million.
Extended Abstract (992K)
Session 8, Case Studies: Part II (ROOM 605/606)
Monday, 12 January 2004, 4:00 PM-5:30 PM, Room 605/606
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