Storm Wind Frequency and Direction, Dempster Highway, Richardson Mountains, Yukon and Northwest Territories

摘要

Maintenance costs have risen since 1996 along the northern Dempster Highway, especially for snow clearing. The purpose of this paper is to investigate the wind regime of the region and determine its association with increased maintenance activities. Hourly wind speed and direction were measured at four sites near the territorial border crossing (YT km 465/NT km 0) for July 2006-December 2018 at the Environment Canada Rock River station (YT km 457) and February 2014 to July 2018 at YT km 421, NT km 8.5, and NT km 51.5. Wind speeds were classified according to the Beaufort Scale and wind type: calm (force 0-1), breeze (2-6), gale (7-9), and storm (10-12). The mean winter wind speed was highest at Rock River (4.1 m/s), followed by km 8.5 (2.4 m/s), km 421 (2.3 m/s), and km 51.5 (2.1 m/s). At all sites the mean wind speed was lower in winter than summer, but the highest winds were measured in the winter. At Rock River, 9.1 % of observations were for gale or storm winds, considerably more than at kms 8.5 (0.5%), 51.5 (0.1%), and 421 (1.1%). In Yukon the dominant and strongest winds were easterly off Richardson Mountains, while in the NT the dominant winds were southwesterly, but more variable in direction. There were no apparent increases in winter wind speeds over the period of record. Although Rock River experienced the strongest winds throughout the year, it exhibited the same seasonal trends in wind speed as the other locations. The dominant easterly wind direction at Rock River was consistent with km 421. The valley near Rock River is well nicknamed Hurricane Alley.