Los Angeles Flood of 1938

Los Angeles Flood of 1938
Name	Los Angeles Flood of 1938
Caption	Aerial view of flood damage in the San Gabriel River basin
Date	February 1938
Location	Los Angeles County, San Gabriel Valley, San Fernando Valley, San Bernardino County, Ventura County
Fatalities	~115–200
Damages	~$78,000,000 (1938 dollars)

Los Angeles Flood of 1938 The 1938 flood was a catastrophic series of winter storms that produced massive runoff across Southern California, overwhelming rivers, washes, and urban drainage systems in Los Angeles County and adjacent counties. The event catalyzed large-scale federal, state, and local interventions involving agencies and public figures and reshaped water and flood management across the Los Angeles Basin, the San Gabriel Valley, and the Los Angeles River watershed.

Background and Causes

A strong Pacific atmospheric river and repeated cyclones in January–February 1938 tapped moisture from the North Pacific Ocean and the Gulf of Alaska jet stream, producing intense precipitation over the Sierra Nevada and the Transverse Ranges. Antecedent conditions included saturated soils after heavy rains in January and extensive runoff from the San Gabriel Mountains, Santa Monica Mountains, and San Bernardino Mountains. Urban expansion in the City of Los Angeles and suburbanization in the San Fernando Valley and Pomona Valley had increased impervious surfaces, reducing infiltration in the Los Angeles River and tributary basins such as the Rio Hondo and Santa Ana River. Land use changes following the Great Depression and infrastructure inadequacies highlighted by earlier events such as the Los Angeles River flood of 1884 set the stage for extreme flood impacts.

Course of the Flood

A series of three storms between late January and mid-February produced peak discharges that crested at different times along the San Gabriel River, Los Angeles River, Santa Ana River, and smaller arroyos. Hillslope failures and debris flows in burn-scarred areas from previous wildfires increased sediment loads in channels draining into Montebello, Whittier, Long Beach, Pasadena, Burbank, and the San Fernando Valley. Levee breaches along the Los Angeles River near Downtown Los Angeles and downstream crevasses near Long Beach allowed floodwaters to inundate industrial districts, rail lines of the Southern Pacific Railroad and Santa Fe Railroad, and neighborhoods near the Port of Los Angeles. Simultaneous overbank flows on the San Gabriel River and Santa Ana River compounded flooding in the Pomona Valley and Riverside County floodplains.

Impact and Casualties

Human tolls included at least a hundred fatalities, with estimates varying between sources and reports from the Los Angeles Times and federal investigators; many victims were residents of low-lying neighborhoods and communities in the Whittier Narrows and San Fernando Valley. Damage to transportation infrastructure affected the Pacific Electric Railway, Union Station connections, and highway bridges on U.S. Route 101 and US 101 corridors. Industrial losses hit oil facilities in Long Beach and refineries near the Harbor Gateway, while agricultural damage struck citrus groves in the Riverside and Orange County orchards. The storm affected installations such as Los Angeles Municipal Airport (now LAX) and military properties linked to Fort MacArthur and March Field; its disruption of rail and port commerce rippled through the United States economy during the late Great Depression.

Response and Relief Efforts

Local agencies including the Los Angeles County Flood Control District and the City of Los Angeles Fire Department conducted rescues alongside volunteer organizations and civic groups. The Federal Emergency Relief Administration and later the Federal Emergency Management Agency predecessors were involved in disaster assessment and aid, with the Works Progress Administration and the Civilian Conservation Corps mobilized for emergency repairs and debris removal. The flood prompted hearings in the United States Congress involving the United States Army Corps of Engineers and testimony from officials in the California State Legislature; emergency funds were allocated and temporary shelters operated in Dodger Stadium (then Chavez Ravine) and school gymnasia in East Los Angeles and San Gabriel. Philanthropic efforts by organizations such as the American Red Cross coordinated relief with local churches and neighborhood associations.

Infrastructure Changes and Flood Control Measures

The scale of destruction prompted the United States Army Corps of Engineers to undertake massive channelization and levee projects across the Los Angeles River and tributaries, including concrete lining and grade-control works through Downtown Los Angeles and the San Fernando Valley. The Los Angeles County Flood Control District accelerated construction of debris basins, detention reservoirs, and new flood-control dams in the San Gabriel Mountains and Santa Ana Mountains, while state programs funded retention structures and watershed management projects tied to the California Department of Water Resources. Major projects included redesign and construction of the Whittier Narrows Dam, Sepulveda Dam, and Santa Fe Dam. Railroads rebuilt bridges and elevated tracks to improve resilience along the Southern Pacific Railroad and Union Pacific Railroad rights-of-way. The flood control program reshaped urban planning in the City of Los Angeles and surrounding municipalities like Glendale, California, Pasadena, California, and Burbank, California.

Economic and Social Consequences

The immediate economic cost—estimated in the tens of millions of 1938 dollars—affected shipping at the Port of Los Angeles, industrial output in the Harbor Gateway and East Los Angeles, and agricultural productivity in Riverside County and Orange County. Insurance markets and banking institutions in Los Angeles County faced claims that influenced lending for reconstruction and suburban development. Socially, the flood highlighted disparities in housing and infrastructure between affluent neighborhoods such as Bel Air and working-class districts including Vernon and Watts, accelerating policy debates in the California Legislature and local councils. The reconstruction period interacted with New Deal programs and wartime mobilization policies that would later affect urban growth and the Defense Industry buildup in Southern California.

Legacy and Commemoration

The 1938 event remains a pivotal reference in studies by institutions like the United States Geological Survey and academic programs at UCLA and University of Southern California for flood risk, urban hydrology, and disaster mitigation. Physical legacies include the concrete-lined channels of the Los Angeles River and extensive flood-control reservoirs that define modern Los Angeles County landscapes. Memorials and exhibitions at regional museums and civic institutions commemorate victims and engineering responses, while annual reviews in publications such as the Los Angeles Times and reports by the Army Corps of Engineers revisit lessons for contemporary climate variability and stormwater management. The event influenced later legislation and planning paradigms in California flood policy and remains a benchmark for emergency preparedness in the United States.

Category:1938 natural disasters in the United States Category:Floods in California