Abstract
Data on explosively developing extratropical cyclones over the northeast portion of the Pacific Ocean have been compiled. A climatology of those events which deepened by 1 Bergeron (24 mb day−1 deepening at 60°N) or more is discussed. The maximum number of events occurred in October and the minimum number in August. The initial positions of such storms was most frequently in the area between 40 to 50°N and 140 to 170°W.