The 1906 San Francisco Earthquake and Fire—Enduring Lessons for Fire Protection and Water Supply

Prior to 18 April 1906 the San Francisco Fire Department and knowledgeable persons in the insurance industry regarded a conflagration in San Francisco as inevitable. The 1906 San Francisco earthquake and ensuing fire is the greatest single fire loss in U.S. history, with 492 city blocks destroyed and life loss now estimated at more than 3,000. This paper describes fire protection practices in the United States prior to 1906; the conditions in San Francisco on the eve of the disaster; ignitions, spread, and convergence of fires that generated the 1906 conflagration; and damage to the water supply system in 1906 that gave impetus to construction of the largest high‐pressure water distribution network ever built—San Francisco's Auxiliary Water Supply System (AWSS). In the 1980s hydraulic network and fire simulation modeling identified weaknesses in the fire protection of San Francisco—problems mitigated by an innovative Portable Water Supply System (PWSS), which transports water long distances and helped extinguish the Marina fire during the 1989 Loma Prieta earthquake. The AWSS and PWSS concepts have been extended to other communities and provide many lessons, paramount of which is that communities need to develop an integrated disaster preparedness and response capability and be constantly vigilant in maintaining that capability. This lesson is especially relevant to highly seismic regions with large wood building inventories such as the western United States and Japan, which are at great risk of conflagration following an earthquake.