Fire Disaster Information

Frequently Asked Questions on Post-Fire Flooding and Debris Flows and Protective Measures

What are the flooding and debris flow impacts that could potentially occur after a fire? For how long after the fire am I facing the potential impacts?

Flooding and debris flows can occur during storm events. The potential for debris flows can occur in and below the areas where fire has denuded of vegetation and altered the characteristics of the topsoil. The extent and amount of flows will depend in the rainfall intensity and duration of the storm event, and on the extent of recovery of vegetation in the burn areas at the time. These flows can be highly destructive and move large quantities of soil, rocks, brush and trees into neighborhoods, causing property damage, blocking streets and endangering property occupants. It can take about four to five years for the burn area vegetation to significantly recover, about ten years to fully recover.

Where can I immediately get information on protecting my property from flooding and debris flow impacts?

Los Angeles County Department of Public Works has prepared a booklet entitled: "The Homeowner's Guide for Flood, Debris and Erosion Control" to assist property owners in identifying measures they can take to help protect structures on their properties from flooding and debris flow impacts. You can obtain a copy by calling us at (626) 458-6164. The booklet can also be found on our web site at

If you live in an incorporated area (that is, a city), you can also contact your city's fire department or public works department for information they have on hand.

Where can I get sandbags to protect my property?

If you live in an incorporated area (that is, a city), contact your city's fire department or public works department for information on sandbag pick-up locations. If you live in an unincorporated area, you may pick up sandbags at your local Los Angeles County Fire Station. The County Fire Stations are authorized to provide up to 25 sandbags to you. This limitation is not for the purposes of economy, but to prevent the installation of sandbag structures at such a scale that can potentially adversely impact your and others' properties if they are not located and installed by knowledgeable individuals.

If you have received from County Public Works written debris flow mitigation advice that specifies more than 25 sandbags, the Fire Department is authorized to provide to you the number of sandbags specified in the advice. It is recommended you show the Fire Department personnel a copy of the written advice that was provided to you.

What is the purpose of the debris flow mitigation advice Public Works offers in the fire areas?

The purpose of the advice is to assist Los Angeles County property owners in or below the fire areas in identifying emergency protection measures they can take specific to their properties to protect themselves from mud and debris flows from the burn areas that could occur during the rainy season for the next several years following a fire. We provide mudflow protection advice as a service to property owners at no additional cost to them.

How soon after a fire event would Public Works offer me debris flow mitigation advice for my property? How will I be notified?

We seek to offer in as timely a manner as possible advice to property owners in and below the burn areas. We aim to contact these property owners within a couple of weeks after the fire has been fully contained. The actual length of time it takes to contact the owners will depend on several things: the magnitude of the fire; how quickly the authorities deem it safe for us to access the area for field assessment; how quickly we can get burn boundary information; the number of properties we identify as potentially benefiting from advice.

In County unincorporated areas we will proceed with obtaining the names and mailing addresses of potentially impacted property owners. We will mail to them our offer to provide them with advice on measures they can take on their properties to help protect themselves from post-fire mud and debris flows during the upcoming rainy season and the next several years.

In incorporated (that is, city) areas we will notify the city of our field findings in regards to potentially affected properties within city boundaries. The city will then determine what subsequent actions it will take. We will proceed to offer advice to potentially affected property owners in the city if the city requests our services. Upon getting that request from the city and the mailing addresses of potentially affected property owners, we will mail to them our offer to provide them with mudflow advice. Our notification process and timelines may vary to comply with a city's notification policies.

For fires that occur right before or during the rainy season (October 15 to April 15), we will seek to expedite assistance by initially notifying property owners/occupants in person. In incorporated areas such action on our part will be subject to concurrence from the city.

I lease or rent my place. Will Public Works notify me and provide me debris flow mitigation advice?

We will endeavor to notify the owner of the property and the property manager, since protection of the property is ultimately under their authority. In cases where a fire has occurred right before or during the rainy season, we may seek assistance from occupants in contacting the property owner and/or property manager to expedite assistance.

If you occupy a property that is owned by the U.S. Forest Service, protection measures are under the Forest Service's authority and responsibility. Please contact the Angeles National Forest District Office at (626) 574-1613 for assistance.

Ok, I want to accept Public Works' offer of debris flow mitigation advice. What do I do?

Call the contact person named in our notification to you. If you do not have the notification, call Public Works at (626) 458-6164 to set up a time for us to consult with you on the site. We will need your permission to access your property to identify appropriate protection measures. Walking around your property with you allows us to enhance your understanding of the measures we are recommending and what they can do for you.

In what form is the debris flow mitigation advice given?

Our advice to you will be in the form of a package. The advice package will contain:

  • A form that specifies the measures we are recommending for your property and a rough sketch of where these measures are to be placed. If we are recommending sandbag placement, the form will specify the approximate number of sandbags needed to implement the advice we are giving.
  • A copy of our "The Homeowner's Guide for Flood, Debris and Erosion Control." You can call us at (626) 458-6164 to obtain another copy. The Guide is also on our web site at
  • Fact sheets on flood insurance.
  • A Customer Satisfaction Survey form and a pre-stamped envelope addressed to us. The Survey Form provides you the opportunity to provide at your convenience feedback to us on the quality of our service to you. We will look forward to hearing from you!

The advice we provide you in this package are temporary measures that will be based on a field review of your property that will be limited in scope due to time constraints imposed by the timing of the fire in relation to the rainy season and the need to provide timely advice to other property owners. Please note flooding, mudflows, and debris flows emanating from the burned canyon and hillside areas are extremely unpredictable. The measures we suggest are not intended to protect against all potential damage or injury that may result from such events. You may consider consulting a qualified private civil engineer (registered in the State of California) with experience in drainage matters to conduct a comprehensive evaluation of your property and the upstream watershed area to review what additional temporary or permanent measures you can take.

We will provide copies of your advice package to:

  • Your city (for distribution to the appropriate city departments)
  • Los Angeles County Fire Department (for distribution to your local County Fire Station, to verify the number of sandbags you need to implement the advice)

Am I required to accept and follow the debris flow mitigation advice Public Works provides me?

No. It is entirely up to the property owner to install the measures identified in our advice recommendations.

What if I don't agree with the debris flow mitigation advice Public Works provides me?

Property owners are free to engage at their own expense their own engineers to provide alternative debris flow mitigation advice or recommendations.

Will Public Works install for me the migitation measures it recommends for my property?

No. Public Works is not authorized to expend public funds to perform such work on private property.

Where can I get assistance in placing sandbags or other measures on my property?

As for other measures you take on your property, you can retain a contractor. You can also look into inquiring at local volunteer organizations in your area, such as Boy Scouts of America troops, churches, etc.

What do I do about debris that deposits on my property?

Removal of debris from private property is the responsibility of the property owner. Public Works is not authorized to expend public funds on such work on private property.