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Riverside County Mobilizes Quickly to Address Eastern Coachella Valley Flash Flood Impacts

September 5, 2023

MECCA – Riverside County today proclaimed a local emergency to respond to the impacts of the flash floods in the eastern Coachella Valley from Friday, September 1 that damaged and washed out local roads and the Oasis Community Park, and created potentially severe health risks to the community with the breach of the Lawson Dump.

The local emergency proclamation calls attention to the significant degree of damage and public health concern in the eastern Coachella Valley from the flash flood that dropped close to two and three inches of rain on communities within a short span of time Friday.

The following is an overview of actions that have been taken, efforts that are under way and collaboration between Riverside County and partner agencies to address the impacts of this local emergency.

The Riverside County Emergency Management Department began monitoring the storm as soon as it was alerted to it by the National Weather Service. Riverside County Fire personnel were in the communities on Friday assisting residents. On Saturday morning (September 2), Emergency Management Department staff deployed to the eastern Coachella Valley communities to conduct assessments of damage.

Lawson Dump
In coordination with CAL FIRE/Riverside County Fire Department, Emergency Management Department crews found that the flooding caused the breach of a dirt and rock retaining wall and berm along the Lawson Dump on Torres-Martinez Tribal land near Thermal, along Pierce Street and Avenue 69.

Three surrounding mobile home parks are flooded with water and unknown materials, with the potential of severe toxic exposure to the residents. These mobile home parks, San Jose Mobile Home Park, Vargas Mobile Home Park and Gamez Mobile Home Park, have been under an evacuation warning since Saturday, September 2.

Within a few hours Saturday, the Emergency Management Department and the Riverside County Department of Public Social Services coordinated with the Galilee Center to open an evacuation center at the Galilee Center in Mecca. Evacuated residents will have a safe place to stay, meals and services.

TODEC Legal Center has assisted with outreach efforts to the impacted community.

County agencies and Supervisor V. Manuel Perez’s office are coordinating to develop strategies to address this situation including engaging the California Governor’s Office of Emergency Services for any assistance they are able to provide.

The Riverside County Department of Environmental Health is conducting initial testing in the field and will coordinate to expedite results from the contracted laboratory. The goal is to receive results 48 hours after submittal. The department will contact the U.S. Environmental Protection Agency to request its response and involvement, and seek further guidance for a complete list of potential contaminants for testing.

The Riverside University Health System – Public Health and the Riverside County Housing and Workforce Solutions Department deployed a team this morning to assess the community for health impacts. The Emergency Management Department has been assisting resources onsite with bilingual staff and coordinating requests to state and federal partners.

The Riverside County Transportation Department, the Riverside County Flood Control & Water Conservation District and the Emergency Management Department are meeting in the field with a contractor today to assess restoration plans.

Several roadways and exit ramps were damaged or completely washed away. The County Transportation Department has posted a list of road closures for county roads affected by flooding in the eastern Coachella Valley. These closures are:

• Hammond Road in Mecca, from Grant Street to Avenue 68
• 72nd Avenue in North Shore, westerly to Sea View Drive
• Fillmore Street in Thermal, from Avenue 52 to Avenue 54
• Pierce Street in Oasis, from Avenue 66 to Harrison Street
• Harrison Street in Oasis, from Avenue 70 to Avenue 81
• Johnson Street in Oasis, from Avenue 81 to Avenue 82
• Van Buren Street in Vista Santa Rosa, from Avenue 66 to Avenue 62
• Avenue 66 in Vista Santa Rosa, from Jackson Street to Van Buren Street.

The Coachella Valley Water District over the weekend worked on Avenue 76 and Pierce Street in the community of Oasis to re-establish access to the mobile home park, where the crossing had been washed out. This has assisted the county, allowing the county transportation department to spread its resources to address other flooding areas.

“The flash floods on Friday came and went quickly but caused significant damage in the eastern Coachella Valley, a lot more so than from Hurricane Hilary,” said Supervisor Perez. “The efforts of our county team and community partners have all been to assist the residents who are having to deal with damage in their communities from this storm. There are many areas that were affected and that’s why we quickly proclaimed a local emergency to seek any eligible potential federal and state assistance to support our repair and recovery efforts.”


Supervisor V. Manuel Perez represents the Fourth Supervisorial District on the Riverside County Board of Supervisors. The largest district in the county by geography, the 4th District covers eastern Riverside County, from Whitewater, stretching across the entire Coachella Valley south to the Salton Sea, up Highway 74 to Idyllwild and the mountain communities, and heading east of the Coachella Valley to Blythe and the Colorado River.

Supervisor Perez’s office hours are 9 a.m. to 5 p.m. Monday through Friday.

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Thermal Flooding