The first storm of the season swept through West Marin last week, unleashing fierce winds and three days of unrelenting rain. The deluge was tied to a powerful weather system churning over the northeastern Pacific Ocean just offshore of Oregon and Washington. According to meteorologists from the National Weather Service, the system set a record for the lowest barometric pressure reading ever recorded in that area of the ocean—plunging to 942 millibars, rivaling the intensity…