Surface winds during an intense outbreak of arctic air in Southwestern British Columbia

Abstract

An outbreak of arctic air which occurred from 30 January to 2 February 1989, plunging southwestern British Columbia (as well as most of western North America) into extreme cold, is examined and put in context by reference to similar events reported in the literature. Emphasis is placed on the resulting wind fields in Howe Sound and the Lower Fraser Valley. The wind speed in these topographically confined channels during arctic outbreaks is found to be related to the down-channel pressure gradient. Three simple steady-state models of wind speed are suggested whose results are compared to observed winds. It is found that the Friction model, representing a balance between friction, acceleration and horizontal pressure gradient, compares best with observations in the Lower Fraser Valley. Hydmod, a hydraulic model of wind flow performs reasonably well, with previous work indicating it produces more realistic along channel flow variability in Howe Sound. © 1996 Taylor & Francis Group, LLC.