The northwest United States is visited frequently by strong midlatitude cyclones that can produce hurricaneforce winds and extensive damage. This article reviews these storms, beginning with a survey of the major events of the past century. A climatology of strong windstorms is presented for the area from southern Oregon to northern Washington State and is used to create synoptic composites that show the large-scale evolution associated with such storms. A recent event, the Hanukkah Eve Storm of December 2006, is described in detail, with particular attention given to the impact of the bent-back front/trough and temporal changes in vertical stability and structure. The discussion section examines the general role of the bent-back trough, the interactions of such storms with terrain, and the applicability of the ''sting jet'' conceptual model. A conceptual model of the evolution of Northwest windstorm events is presented.

Central. He is currently completing his Master's degree in Alternative Energy Technologies at ASU. ASU-PTL is the only accredited design qualification laboratory in the United States. ASU-PTL has tested more than 3000 PV modules and issued more than 280 qualification certificates. ASU-PTL participates in the development of national and international standards of ASTM, IEEE and IEC.