Can wildfires increase the risk of flooding?
Last updated: September 2021
Wildfires burn millions of acres of land each year, according to the Insurance Information Institute. But even after a wildfire is put out, danger can still linger. Areas that have experienced a wildfire can be at a higher risk for flooding. Here's a look at why wildfires increase the risk of flooding and some steps you can take to help prepare your home and your family.
Why are wildfire areas at risk for floods?
Land that has been burned by a wildfire is often left with a burn scar, which results from the vegetation being burned off, says the National Weather Service (NWS). Burn scars leave the ground very dry and unable to absorb water, and the terrain can even become as dense as pavement. This means post-wildfire areas typically have an elevated risk for flash floods.
Types of flooding events in wildfire areas
Here's a look at the types of flooding events that can occur and why, according to the Federal Emergency Management Agency (FEMA).
- Flash floods: Vegetation normally helps absorb rainfall. But, since burned soil and vegetation leaves the ground hard and unable to absorb water, the risk for flooding increases when it rains. When it rains, a flash flood could occur in as little as 6 hours in low-lying areas.
- Mudflow: Rainwater can pick up large amounts of burned debris and ash that's left behind after a wildfire. This debris combines with floodwater and creates a mudflow.
Less than half an inch of rain in an hour can trigger these types of floods, according to the NWS. And, even if you weren't directly affected by a wildfire, you can still be at an increased risk for flooding. Locations downhill or downstream, for example, are susceptible to fast-moving floodwaters that initiate in a burn area, says the NWS.
Floodwater can wash out roads and damage buildings and homes, so you should make some preparations in advance in case one strikes in your area. It's also important to remember that a burned area can remain at a higher risk for floods for up to five years, until vegetation has had a chance to regrow, says FEMA.
How can I prepare for a flood?
To help you get prepared for an emergency scenario, such as a flood, you may want to take some precautions before one happens:
- Develop an evacuation plan that identifies a family meeting spot, and map out and familiarize yourself with a route to leave the area.
- Gather supplies (such as water, food and first-aid essentials) in a portable container to create an emergency kit.
- Sign up for local emergency alerts (check with your municipal, county or other local officials).
Keep these flood safety tips in mind if you've been warned that a flood or mudflow may occur or is imminent:
- Monitor weather updates and local alerts regularly.
- Follow evacuation instructions from local officials.
- If you're at home when a flood occurs, move to a higher level (but avoid enclosed attics, as you may become trapped by rising floodwater).
You may also find some peace of mind by taking steps to protect your home and its contents against a flood. However, it's important to remember that homeowners insurance doesn't typically cover flood damage. You may want to consider purchasing flood insurance, which helps pay to repair or rebuild your home if it's damaged in a flood.
If your area experiences a wildfire, remember that the elevated flood risk can remain for up to five years. Plan ahead so you can be better prepared, and remember these tips to help you stay safe in case a flood occurs.