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Los Angeles Basin's 1938 Catastrophic Flood Event

Biot Report #369: June 07, 2006 Printer Printer Friendly

The catastrophic 1938 Los Angeles flood event began with a Pacific Ocean storm that moved inland across the basin toward the towering San Gabriel Mountains, deluging the area with 4.40 inches of rain on February 27-28, and the early morning hours of March 1, 1938. This three-day storm, which ended at 5:45 a.m. on March 1, left in its wake a “slowly receding brown flood which had menaced thousands of homes and forced evacuation of only a few dwellings in low-lying areas” of the basin. (2) The 4.40 inches of rain reminded many Angelenos of the New Year’s Day flood in 1934, described elsewhere. (1) Many Angelenos breathed a sigh of relief, thinking that the worst was over, but they were wrong.


After 15 hours of clearing weather, a new oceanic storm swept into Southern California from the North Pacific at 8:45 p.m. on March 1, 1938, bringing with it southeasterly to southerly winds that reached gale force along the coast. (3) Two days later, on March 3, 1938 at 7 p.m., the storm finally abated. Over 10 inches of rain had fallen in just five days. The saturated soils of the San Gabriels had already given way, sending massive debris flows down dozens of steep and narrow canyons that poured their contents onto the Los Angeles basin, like they had been doing for eons.

The 1938 flood event resulted in the deaths of 115 people. It destroyed 5,601 homes and damaged 1,500 homes making them uninhabitable. For many Angelenos, the storm evoked grim memories of the 1934 Los Angeles New Year’s Day flood in which 40 people, 200 homes, and 800 mostly Model “A” cars perished in the water and mud. (1) In both storms debris flows and watery mud buried people in their homes or drowned them as they attempted in their automobiles to cross roads that had become raging torrents or cross bridges that then washed out, plunging them into the river torrents below. One 58-year-old man named WE Strong “tried to drive his car over a mud-covered road at Colton. He overexerted himself in attempting to get the automobile out of the mud and then slumped in the driver’s dead of a heart attack.” (2)

In one doleful situation, a roaring wall of water accompanied by a landslide swept down upon a house in Beverly Glen, burying 26-year-old Mrs. Rachel Whitman and her 1 and ½-year-old son Donald. Mr. Oliver Whitman, 36 years of age, cheated death. He was taking a bath in the house when the avalanche overwhelmed the structure, and was carried with the bathtub several hundred yards down the canyon. Both of his elbows were broken. He was taken to Valley Hospital, Van Nuys, in serious condition, where the  bodies of his wife and son awaited him. (3)

Aerial Surveillance of Storm Damage

A United Air Lines “Mainliner” took a Los Angeles Times reporter and cameraman to 3,000 feet to assess the damage. “From 3000 feet, a scene unfolds that groundlings can never grasp,” wrote the reporter. “Disaster, gutted farmlands, ruined roads, shattered communications, wrecked railroad lines—all leap into sharp-etched reality from that altitude.” For two hours, the plane flew across “250 miles of flooded Southland, across Los Angeles county to Riverside, the to San Bernardino, south along the rampant Santa Ana River to the wasted coastlands north of Newport Beach, and finally back over inundated Anaheim and Fullerton to Burbank.” (4)

The reporter noted that although Los Angeles County was stricken, “Los Angeles can congratulate herself: Riverside and Orange took the brunt of the waters. Low-lying, they held the flood like gargantuan saucers.” (4) The reporter was most impressed with the swollen “crazy-mad” Santa Ana River that at the time looked like a slightly smaller version of the Mississippi River. “Probably Foothill Boulevard can’t offer ten miles without a washout or a wrecked bridge. Toward Riverside, one bridge in three seemed to have caved in.” The San Gabriel and Puddingstone Reservoirs were “overfull, like a brimming cup of coffee” and “groaned with the weight of [their] waters,” the reporter wrote. (4)

Scores Trapped in San Gabriel Mountains

Scores of people, who were in the San Gabriel Mountains for one reason or another, were either killed or stranded and required rescue. For example, a plane piloted by Deputy Sheriff Dan King over Soledad Canyon, sighted “six groups of marooned persons, aggregating at least ninety. He dropped parcels of food.” (5) Mrs. EM Sawyer and her daughter Genevieve were rescued from the top of the Edison power plant two and one-half miles up the Soledad Canyon. The caretaker of the plant perished in the floodwaters. Tujunga Canyon was all but swept clean of structures that were not up above the flood line. Thirty persons were marooned at Vogel Flats, about seven miles up from the mouth of Tujunga Canyon. The Forestry service lost a guard station, garage, ranger station, equipment, and two trucks, one a large tank truck. A Civilian Conservation Corps (CCC) camp lost a large dining hall, dormitories and other buildings, and 190 relief workers in the camp needed to use an overhead cable across the canyon to escape to safety. All the roads were completely washed out and Forestry crews began to build new roads just to bring marooned people out. (5)

In the Arroyo Seco, between 20 and 25 cabins were lost but there were no deaths. Camp Oakwilde suffered heavy damage, but the lodge stood. At Fish Canyon, 15 cabins were gone, including a Metropolitan Water District building at a tunnel portal. In San Gabriel Canyon, great portions of the road were swept out. In San Antonio Canyon, a CCC camp was wiped out—all buildings were gone except the store room. About 125 men at the camp were evacuated. Mrs. Helen Croy, wife of Governor John Croy of Alaska, was marooned in a cabin at Camp Rincon above San Gabriel Dam No. 1, but eventually reached safety. (5) 


The Los Angeles area was all but isolated from the outside world when the three transcontinental railroads servicing the Los Angeles area stopped operations because of bridge washouts and flooded lines. The Pacific Electric Railway, an interurban line, was crippled because of washouts and bridges destroyed by the floods, halting service between Los Angeles and foothill cities. (3,7)

Telephone, Electric and Gas Companies

Public utilities were swamped by calls reporting broken gas mains, felled power and light poles, and crippled telephone service. Early in the day a portion of the downtown Los Angeles traffic signal system failed, adding further confusion to streets choked by stalled automobiles and slowly moving street cars. There were minor interruptions, which the utilities were able to remedy by March 3, 1938, according to one source. (3)

Schools, Health Care, Public Health, Red Cross, US Postal Service

Schools were everywhere closed because of submerged playgrounds and flooded basements. Ambulances and emergency equipment were busy throughout March 3 answering calls. In one story, an ambulance from the Hollywood Receiving Hospital was making a mercy call in Laurel Canyon, when it found itself blocked by a landslide. When it attempted to leave the area, a huge tree fell, blocking the highway. (3) In the Inglewood area of Los Angeles, sewage lines degraded, resulting in the need to evacuate more than 30 families in a fleet of trucks commandeered by City Councilman Trulove. The Red Cross made preparations to feed these and thousands of other evacuated people from many points in the Los Angeles basin.

The US Coast Guard undertook mail service by boatload between San Diego and Los Angeles. Patrol boats searched the mouth of the Los Angeles River to search for the bodies of possible flood victims, but did not find any by March 4, 1938. The Coast Guard noted a lot of wreckage. The USS Arizona, hovering seven miles offshore of the Los Angeles area coastline reported spotting wreckage that appeared to have come from the Los Angeles River and that had drifted together by the wind and tide. (7)

But, It Could Have Been Worse: Flood Control Systems Mitigated Damage, Especially to Los Angeles County

The Los Angeles drainage basin in 1938 already contained 14 flood control dams. “The story of what the flood control system did is principally told in the fact that behind the fourteen flood control dams, some of them perched high in the mountains, there was enough water being held to cover 105,336 acres a foot deep. Had all that water come down on the valley along with the runoff that could not be captured or had to be released gradually, the damage seen in many quarters would have bee far great and areas that escaped damage would have suffered greatly.” (6)

The chief flood control engineer for Los Angeles County at the time, CH Howell, worked without sleep for days. Haggard and worn, he said that the flood control system functioned “very well”. The storm put the greatest test on the system since its inception. For the first time in the history of the Los Angeles basin flood control project as a whole, the 14 dams in the system were brimful of water on March 3, 1938.  The keystone dam for the Los Angeles River, the Hansen Dam, was incomplete, which deeply bothered the flood control engineers. Thus, the Big Tujunga water flows came roaring out of the canyon with a flow of 40,000 cubic feet per second, the largest flood on that river in decades. Much of it jumped out of the channel and into an old channel between Van Nuys and Lankershim, and into the Los Angeles River. The Los Angeles River was already taxed heavily with the natural run-off from the upper San Fernando Valley, the north slope of the Santa Monica Mountains and the Santa Susanna Mountains rimming the valley. (6)

Once the Big Tujunga flow joined the Los Angeles River, the new channel work undertaken by the US Army Corps of Engineers sustained damage. The roaring water reached behind the new walls and rip-rap work. Up in the Verdugo Wash country, the US Army Corps of Engineers were rebuilding a bridge over the wash to conform to the wider channel at Canada Boulevard. They were awaiting the arrival of steel for the work. Water penetrated behind these channel walls as well where an open section awaited the completion of the bridge. 

The flood engineers were exuberant that flood control dams high up in the San Gabriel Mountains handled huge amounts of water. For example, “San Gabriel No. 2, farthest up on the San Gabriel River, began spilling [over its spillway] into the river and into San Gabriel No. 1 at the rate of about 20,000 cubic feet per second. This combined with the runoff below and from the East Fork poured into the huge San Gabriel No. 1 reservoir an estimated 100,000 cubic feet of water per second at the peak flood. Had it not been for that dam all that water would have gone roaring into the San Gabriel [River].” (6)

Then, San Gabriel “No. 1 began spilling about 60,000 second feet into the [San Gabriel] river and into the reservoir behind Pasadena’s Morris Dam. Engineer Morrise Jones of Pasadena was letting out about 30,000 second feet at the request of the flood control engineers and his reservoir knocked the peak off the flood coming out of San Gabriel No. 1.” (6)

The Los Angeles River at its peak roared about 38,000 cubic feet of water per second. Were it not for the Big Tujunga Dam, which finally filled to capacity and began spilling, the flood on the Los Angeles River would have been much worse than it already was. Engineers were anxious to complete construction of the Hansen Dam to solve much of the problem associated with the Big Tujunga flow. (6)

Plans for a More Comprehensive Flood Control System

As a result of the horrific 1938 flood event in Los Angeles Basin, the US Congress eventually approved with the Flood Control Act of 1941 a new comprehensive flood control plan. (8) This act authorized the US Army Corps of Engineers to reshape Los Angeles County’s natural hydrology into a “monolithic system of concrete storm sewers,” according to writer Mike Davis who despises the look of concrete. (8)

The new comprehensive plan emphasized a three-prong approach, according to author Blake Gumprecht. First, “debris basins were to be built at the mouths of mountain canyons to collect the mud and rock that washed from hillsides during storms and to prevent debris from clogging waterways.” Second, “large flood control basins [e.g., the Sepulveda Flood Control Basin] were to be constructed on the major rivers and their tributary streams to regulate stream flow during storms.” Third, “stream channels themselves were to be deepened, widened, and lined with levees or concrete to enable flood waters to be transported to the ocean as quickly as possible.” (9) This plan would mitigate the effects of rainstorms in the Los Angeles basin and generated thousands of jobs for unemployed people of the depression years of the 1930s.  

One of the biggest problems encountered in building out the flood control structures were the hundreds of homes and railroad yards built along the Los Angeles River and other waterways. “As things stand now,” noted one observer, “there is nothing to prevent a man from selling property in the middle of a wash that gets flooded every year. When a subdivision plan is submitted and perhaps turned down by the engineering, health and other county department and by us, the owners can still sell it.” (10) When the federal government took over flood control of Los Angeles County, it required the county to furnish all land needed for flood control projects. ‘It has been a tremendously expensive thing to go down the channels and buy rights-of-way’” noted HG Legg, chairman of the Los Angeles County Board of Supervisors’ flood control committee. (11)


Will the geology of the Los Angeles basin described elsewhere (1) win out in this epic struggle to manage the hydrological cycles of this treacherous (geologically-speaking) area? Thousands of feet of layered debris flows form the ground on which Angelenos build and live. These thousands and thousands of feet of rubble were washed down from the San Gabriel Mountains from countless storms through countless millennia. The tectonically-active San Gabriel Mountains are rising faster than they are being eroded. (1) Thus, Angelenos are in for a long battle. The storms will continue and so will the debris flows. Will Angelenos, California, and the federal government be able AND willing to devote the resources needed long term to manage the extremely challenging hydrology of the Los Angeles basin? History, according to one writer, says they can’t and they won’t. (12) 


1. SEMP Biot #365:“Infamous New Year’s Day Flood, Los Angeles Basin, 1934” (May 28, 2006) at:; accessed June 7, 2006.

2. “New rainstorm hits Southland: flood danger renewed after brief lull; roads washed and streets choked; 4.40 inches of rain falls in three days.” in Los Angeles Times, March 2, 1938, pp. 1,9.

3. “Thirty dead in Southland floods: Record storm spreads ruin.” In Los Angeles Times, March 3, 1938, pp. 1-2.

4. “Plane trip shows scene of desolation.” In Los Angeles Times, March 4, 1938, pp. 1-2.

5. “Scores trapped in mountains: Pilots report canyon retreats destroyed or heavily damaged.” In Los Angeles Times, March 5, 1938, p. 7.

6. “Small Losses prove value of dam system: Huge amounts of water stored and damage held to minimum” in Los Angeles Times, March 4, 1938, p. 7.

7. “Railroads’ operations remain at standstill: Tie-up of three to seven days seen; Street car and bus service resumes.” In Los Angeles Times, March 4, 1938, p. 9.

8. Mike Davis: “Ecology of Fear: Los Angeles and the Imagination of Disaster”; Metropolitan Books, 1998, pp. 70-71.

9. Blake Gumprecht: “The Los Angeles River”, Johns Hopkins University Press, Baltimore, 2001, p. 208.

10. Ibid, p. 209.

11. Ibid, p. 210.

12. For example, see Sandra Postel: “Pillar of Sand”,  Norton & Company, 1999.