A Case Study of the September 2012 Anchorage Windstorm

On 4-5 September 2012, a severe windstorm impacted the city of Anchorage and the surrounding region. Wind gusts up to 63 mph were reported at the Port of Anchorage, which is just northwest of downtown, and gusts up to 88 mph were reported at McHugh Creek, which is just southeast of Anchorage near the Turnagain Arm. This windstorm downed thousands of trees across the Anchorage Bowl, which caused hundreds of downed power lines. At least 50,000 homes and businesses lost power in the greater Anchorage area during the peak of the event, including some office buildings in the Midtown and Downtown areas of Anchorage. Some areas were without power for several days. This paper will further examine the atmospheric aspects that contributed to the significant September 2012 wind event, as a well as a comparison to the four previous significant wind events that have occurred since 1980. Previous significant high wind events, defined as the "Big Four" by the Anchorage National Weather Service office, occurred much later in the season. The four significant high wind events occurred on 01 April 1980, 26–27 November 1985, 10 October 1986, and 01 December 1992. The results of this paper will provide insight into predicting future wind events which will allow residents and businesses to better mitigate their weather risk.