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.

This content is only available via PDF.
You can access this article if you purchase or spend a download.