Blizzards, hurricane force winds pound California

A mighty hurricane-force Pacific storm continues to clobber California with blizzards, damaging winds, and flooding rains. Hardest hit are the Sierra Mountains, where winds at Ward Mountain near Lake Tahoe were 86 mph, gusting to 163 mph, at 11 am PST. The storm responsible is visible just off the coast of Washington (Figure 1), and has a central pressure near 960 mb--similar to that of a Category 2 hurricane. Blizzard conditions will continue over much of the Sierras, with 2-5 feet likely to fall by Saturday. Travel will be difficult of impossible in the northern mountains of California Friday and Saturday. Snow amounts may reach 10 feet by Monday in some mountain regions of California.


Figure 1. Visible satellite image of the California blizzard of 2008.

The storm pounded the San Francisco Bay area this morning with remarkable ferocity, bringing winds of tropical storm force to the entire region, accompanied by extremely heavy rain. Sustained winds of 53 mph gusting to 67 mph were measured at the San Francisco airport, forcing cancellation of 35 flights. High winds on the Richmond-San Rafael Bridge forced closure of the bridge during the morning commute, when trucks toppled over on both upper and lower spans. Winds gusting to 70 mph were recorded on the Golden Gate bridge. At Mt. Diablo State Park just east of Oakland, sustained winds of 62 mph were reported at 9 am PST. A wind gust of 105 mph was reported at Los Gatos south of San Jose at 12pm PST. Ten inches of rain in 24 hours fell 13 miles southeast of Los Gatos.

In Southern California, the concern is heavy rain and flooding. Rainfall rates of up to an inch per hour are expected in the mountains, with total rain amounts of up to 10 inches expected in the south facing mountains. Landslides and debris flows are likely on the hillsides burned by the recent fires. Strong, damaging winds are expected over much of Southern California, as well. High winds over the the ocean will bring swells of 6-10 feet to the coast and 20 foot seas offshore, and isolated thunderstorms could spawn waterspouts. The storm responsible for the wild weather will weaken and move ashore on Saturday over British Columbia, but will still be strong enough to bring additional heavy rains, high winds, and mountain snows to California through Sunday.

Jeff Masters