Tuesday — October 17, 1989 — 5:05pm: While thousands waited at Candlestick Park for the third game of the World Series to begin, others throughout the Bay Area hurried home to watch the national pastime on T.V. Suddenly all were startled by the rumbling coming from beneath their feet. Fans at the stadium were certain the complex would collapse into a heap of rubble as the shaking concrete structure creaked and groaned. Elsewhere, streetlights and signs alongside roads and freeways swayed eerily as if being pushed by violent unseen winds. Pedestrians ran to take cover as others stood in awe, watching as the 20-second earthquake, centered 60 miles south of San Francisco and registering 6.9 on the Richter scale, shook the ground from San Diego to western Nevada.
Periodically, Mother Nature’s fault lines ripple and stretch without warning, always catching the stunned public unaware and unprepared. In the early morning of January 17,1994, just a few years following San Francisco’s upheaval, residents of Southern California were ripped from their sleep at 4:03am by an earthquake lasting 10 to 20 seconds and registering 6.7 on the Richter scale. The shaking heavily damaged communities throughout the San Fernando Valley and Simi Valley, and their surrounding mountains north and west of Los Angeles.
The damage and destruction from both earthquakes was immense. The number of lost lives from both earthquakes reached 119, there were more than 12,000 injuries. Citizens left homeless or displaced was well above 33,000. In the Loma Prieta earthquake alone there were 18,306 homes damaged, some beyond repair, and the total damage costs from the two reached over 26 billion dollars.
The USGS (US Geological Survey) estimates that several million earthquakes occur in the world each year. Many go undetected because they hit remote areas or have very small magnitudes. The NEIC (National Earthquake Information Center) now locates about 50 earthquakes each day, or about 20,000 a year, with an average of 20 earthquakes per day in California.
Earthquakes however, aren’t the only culprit in man’s constant struggle against nature and the elements. From December 29,1996 through January 4 1997, the “Pineapple Express” dumped up to 24 inches of rain in parts of Northern California. Levee failures on the Consumnes, Mokelumne, Tuolumne, and Feather rivers caused wide spread flooding. The towns of Wilton, Olivehurst and Modesto were especially hard hit, causing damage into the millions.
Another of nature’s weapons against humanity is wind. Compared with other states California ranks number 32 for the frequency of tornadoes. The part of the Sacramento Valley between Chico and Oroville has been dubbed “tornado alley”. In California, as well as the Great Plains, the most frequent tornado to occur is the F0 (weak, winds less then 73mph), with F1s (moderate damage, winds 73-112 mph) almost as often. At least 25 F2s (considerable damage, winds 113-157mph) have been recorded since 1950, but thankfully, no F3s or greater (F3 sever damage, winds 158-206mph) were ever noted.
Close to home, Contra Costa County has recorded four tornadoes since 1989 — all F0s. On average five tornadoes touch down in California each year. Most occur in the Los Angles Basin and the Central Valley.
Continuing down the list of natural disasters, don’t overlook thunderstorms with lightning. Lightning strikes in California about 250,000 times a year, with about 10 times as many flashes arcing across the sky from one cloud to another. About 20 percent of California’s wildfires are attributed to lighting strikes.
How do cities prepare for such disasters? As an aftermath of the San Fernando Valley earthquake in February of 1971 the state of California added section 65302(g) to the California Government Code. The section states, “ The general plan shall include a safety element for the protection of the community from any unreasonable risks associated with the effects of seismically induced surface rupture, ground shaking, ground failure, tsunami, seiche, and dam failure;…flooding; and wildland and urban fires..”.
The purpose of the Safety Element is to reduce the potential risk of death, injury and property damage that may result from hazards such as fires, floods, earthquakes, train derailment, landslides and other hazards.
The Safety Element must identify earthquake faults, flood areas, areas with a high fire danger and any other locally relevant safety issues; then create policies to minimize the loss of life and property. These policies may be in the form of evacuation routes, peak load water supply requirements, and minimum road widths and clearances around structures, restrictions on new development and redevelopment based on the levels of acceptable risk and potential severity of hazards.
The Safety Element’s identification of local hazards and safety issues provide a crucial guideline to land use decisions. While the Land Use Element identifies areas where hazardous land uses may be located, the Safety Element contains policies for determining acceptable levels of public risk imposed by these land uses, as well as policies for mitigating the effects of natural or manmade catastrophes.
Because of this close connection between public safety and land use, Safety Element policies are also closely coordinated with the policies of the Open Space, Conservation, Housing, and Circulation Elements as they relate to the locations of urban versus open land uses, housing concentrations, and transportation routes.