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.
I. Introduction One of the most powerful extratropical cyclones in the past several decadesswept across the Bering Sea on 8-9 November 2011 bringing widespreadstorm-force winds, high combined seas and coastal flooding over a large part ofwestern Alaska. An unusual aspect of this system was that it occurred veryearly in the season when most of the Bering Sea was ice-free, thus large wavesoffshore and coastal flooding impacted the region. The November 2011 storm'slocation in the Bering Sea, and intensity at that location, made this system anatypical event. We seek to provide a historical perspective of this early season stormcompared to two other potent early season extratropical cyclones that haveoccurred in approximately the same geographic area. These other storms were theNovember 1974 storm and the October 2004 storm. We will explore the large scalemeteorological conditions present with each storm and look to draw acorrelation between climatologic predictors of storms of this caliber. Lastly, a more detailed analysis of the impacts of the November 2011 storm will begiven. II. Historical Perspective The 1974, 2004, and 2011 storms were very similar in their tracks, intensity, and impacts along the coasts of the eastern Bering and Chukchi Seas. Figures 1a-1c show the northward tracks of these storms across the Bering Seawhere they recorded minimum central pressures of 945 mb, 941 mb, and 943 mb forthe 1974, 2004, and 2011 storms, respectively. At their peak, these systemsreached hurricane force, with winds 64 kts or greater. The combination ofstrong onshore flow and large waves generated by each of these systemsinundated coastal communities in the eastern Bering and Chukchi Seas resultingin much damage. Sustained winds reached storm force (44–63 kts) with hurricaneforce gusts in adjacent Alaskan communities. These areas lay to the east of thestorm center, which is somewhat fortunate in that mature extratropical cyclonestend to generate their strongest winds to the south and southwest of the center(Sienkiewicz, et al 2009). Considering the impacts of these systems, predictingtheir occurrence is crucial to protect people and assets in the Bering andChukchi Sea areas. Table 1 shows some meteorological observations from thethree events.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.