Winter Storm and Flooding in California, January 22 to 24, 2008

A Pacific storm reached the central California interior on the 22nd, with heavy snow falling across the length of the Southern Sierra Nevada and the Tehachapi Mountains. A persistent rain band over the west side of the San Joaquin Valley brought locally heavy rain to the Temblors and Diablo Range on the 23rd. Runoff from these mountains caused some road flooding in western Fresno and Kings Counties. Several inches of snow fell on the Grapevine beginning on the 22nd, and in the Los Angeles County mountains near Gorman. At Frazier Park, about 1000 feet higher than the Grapevine, a spotter measured 18 inches of fresh snow. Interstate 5 was closed at the Tejon Pass late in the afternoon of the 23rd, with one report estimating that the number of stranded cars was over one hundred. The Interstate remained closed through the 24th, before finally reopening the next morning.

The very cold airmass accompanying the storm caused snow to fall on the Temblors and Diablo Range on the west side of the San Joaquin Valley during the afternoon of the 23rd. Two to four inches of snow fell down to elevations between 1500 to 2000 feet. Local media reported Highway 198 closed west of Coalinga due to snow. Traffic Management indicated the closure was from Firestone Avenue west to the Monterey County line. Temporary closures also occurred on Highways 41, 46, and 166 due to snow, effectively shutting down exit routes from the San Joaquin Valley to the west, with exit routes to the south already shut down along the Grapevine and Tehachapis. Los Gatos Creek Road and Parkfield Grade were also closed during the afternoon of the 23rd due to the snow.

However, with the upper-level low remaining offshore, there initially was a fairly sharp boundary marking the edge of the precipitation between the western valley and the eastern valley. Rain was slow to spread into the eastern half of the San Joaquin Valley, and many locations in the Southern Sierra Nevada received less than a foot of new snow.

When the precipitation band finally shifted eastward during the evening of the 23rd, locally heavy rains caused some street flooding in Fresno, Kings and Madera counties.