Flooding in California, January 1 to 27, 1997

Several periods of rain (with snow to unusually low elevations in the mountains) beginning December 20, 1996, set up saturated conditions that finally gave way on the 1st as subtropical air moved in and melted snow up to the 8000-foot level. The moist airmass also left huge amounts of additional rain in the valley, foothills, and mountains with its nearly ideal orographic enhancement conditions. Some of the higher amounts from December 26 to January 3 follow:Shasta Lake inflow area: Stouts Meadow 36.39 inches Shasta Dam 23.70Feather River basin: Four Trees 41.32 Bucks Lake 42.16Yuba River basin: Strawberry Vly 32.80American River basin: Blue Canyon 29.73Stanislaus River basin: Gianelli 18.66Sacramento River valley: Redding 5.29 Sacramento 3.71At Bucks Lake, rainfall rates were 6.94 inches in 12 hours, 12.16 inches in 24 hours, 20.72 inches in 48 hours, and 27.56 inches in 72 hours. At most locations, the highest rates occurred on the 1st and 2nd.A dry spell from the 3rd to the 11th allowed the flooding to subside in the Shasta-Cascades and the Sierra Nevada mountains, but flooding worsened in the valley below. As the runoff moved downstream and flood control dams operated at near maximum releases, stress on the Sacramento River and San Joaquin River levees resulted in numerous levee breaks, especially from the 4th to the 10th. The result was considerable inundation of the areas near the break. The major breaks for which separate damage figures were available are broken out below. Heavy rains returned at the end of the month, beginning on the 22nd and lasting through the 27th. These storms were colder in nature, with flooding problems mainly in the foothills and valley floor. Levees continued to break in the Sacramento-San Joaquin River delta as the floodwaters headed out to San Francisco Bay.Preliminary data indicated record peak stages were set at nine river gages in the Sacramento-San Joaquin river system. The particular rivers include the Sacramento, San Joaquin, San Joaquin Eastside Bypass, Feather, and especially the Cosumnes and Tuolumne Rivers.The variety and magnitude of the damage were huge. Besides 5 deaths (all accounted for in the entries which follow) in interior northern California, at least 120,000 total people were evacuated. The flooding damaged or destroyed 20,000 homes and 1500 businesses, at a minimum, in the estimated 250 square miles that were inundated. The toll in dollars will be measured in the billions; early estimates put the total bill for the state at $1.6 billion, much of it in interior northern California. Infrastructure took the hardest hit, conservatively estimated at $400 million for roads and $300 million for flood control facilities. Agricultural damage estimates of $250 million is expected to increase. Hardest hit included the artichoke and winter wheat crops, and the dairy industry, losing thousands of livestock drowned. The flooding also virtually destroyed two large fish hatcherys, the Feather River fish hatchery and the San Joaquin fish hatchery. The American Red Cross labeled the flooding a level 5 disaster--their highest rating.