The 1923 Berkeley fire was a conflagration which consumed some 640 structures, including 584 homes in the densely built neighborhoods north of the campus of the University of California in Berkeley, California on September 17, 1923.
Although the exact cause was never determined, the fire began in the undeveloped chaparral and grasslands of Wildcat Canyon, just east of the ridgeline of the Berkeley Hills, and was propelled over the ridge and southwestward just south of Codornices Creek by a strong, gusty, and intensely dry northeasterly wind. The fire quickly blew up as it swept through the La Loma Park and Northside neighborhoods of Berkeley, overwhelming the capabilities of the Berkeley Fire Department to stop it. A number of UC students fought the advance of the fire as it approached the north edge of the University of California campus at Hearst Avenue. The other edge of the fire was fought by firefighters as it advanced on downtown Berkeley along the east side of Shattuck Avenue north of University Avenue. Firefighters were rushed in from neighboring Oakland while San Francisco sent firefighters by ferry across the bay.
Firefighting efforts were hampered by the inadequacy of water mains in north Berkeley, where rapid development after the 1906 San Francisco earthquake had outgrown the water supply in the fire area. Firefighters trying to fight the fire connected to hydrants in the fire area that hissed dry. Firefighting was also hampered by the predominance of cedar shake roofs in the fire area. The strong and dry Mono Winds lifted burning shakes off burning houses and quickly spread the fire. The fire was only halted when 1) the Mono winds died down and were replaced by the cool, humid afternoon sea breeze; and 2) fire-lines were established at Hearst and Shattuck Avenues where larger diameter water mains delivered a reliable water supply for firefighting.