Skip to Main Content

Media Resources

California's Rainy Season

Heavy rains from late October through March mark the rainy season in California, bringing the majority of yearly rainfall to the region. Each year during the winter rainy season, Californians face the risk of flooding and mudflows that can damage homes and businesses.

Winter floods can strike at any time. Already this season, major flooding has impacted thousands of residents in the Pacific Northwest. Californians are equally as vulnerable; it is important for California residents to protect their property from flood damage year-round. Only flood insurance offers financial protection from flooding.


A string of large-scale wildfires in 2006 have dramatically altered the landscape and ground conditions in the state. Wildfires have scorched more land in 2006 than in any year since 1960, burning an area twice the size of New Jersey. In California, more than 600,000 acres have been destroyed this year (source: National Interagency Fire Center) from San Diego to areas throughout the Central Valley.

The charred and denuded ground in burned areas cannot absorb water easily, making them especially susceptible to flooding, mudflows, mudslides and landslides. Properties that were directly affected by the fire as well as those located below or downstream of the burned areas will all be at risk once the winter rainy season commences. Experts state that, after a wildfire, it can sometimes take three to five years for the vegetation to return to its previous state. Without this vegetation and ground cover, rainfall can cause soil on steep slopes to become saturated, liquefy and then flow down hills as a powerful and devastating mudflow.


California has thousands of miles of levees�embankments along waterways, usually made of earth, designed to protect the lives and properties behind them from floods. However, no levee provides full protection from flooding and increased rains during the winter months can affect the ability of a levee to effectively contain rising waters. All levees are designed to provide a specific level of protection, and can be overtopped, or fail, in larger flood events. Levees also require regular maintenance to retain their level of protection. The fact is, levees can and do decay over time, and maintenance can become a serious challenge. When levees do fail, or are overtopped, they fail catastrophically�the flood damage may be more significant than if the levee was not there. For these reasons, the millions of people on the West Coast living behind levees need to understand the flood risks they face and take steps to address them.

Mudflows v. Mudslides
A mudflow is a flooding condition where a river of liquid and flowing mud moves on the surface of normally dry land areas. Mudflows are different from mudslides, in which a dry or wet mass of earth or rock moves downhill. Though a flood may trigger a landslide, damage is caused by the falling mass of rock or earth, not the water.

Mudflows are covered by flood insurance�mudslides are not.
If your community contains a levee, there are things you can do to protect yourself and reduce the impact of flood events. First, be sure you understand your risk for flooding. Local officials can provide more information about the levee and related flood risks based on the location of the property. Second, obtain flood insurance�it is critically important to financially protect your investment. Although areas behind levees that can be shown to protect against the one-percent-annual-chance flood will be shown on flood hazard maps as moderate-risk areas, FEMA strongly recommends flood insurance protection for all properties behind levees. Finally, please be aware of and always adhere to local evacuation procedures.


Residents in areas susceptible to winter flooding need to prepare in advance for flood conditions. Before the threat of flooding becomes imminent, residents should:

  • Purchase a flood insurance policy if they do not already have one
  • Review their current insurance policy and become familiar with what is and is not covered
  • Make a flood plan. Plan evacuation routes. Keep important papers in a safe, waterproof place.
  • Itemize and take pictures of possessions

Consumers can visit or call 1-800-427-2419 to learn how to prepare for floods, how to purchase a National Flood Insurance policy and the benefits of protecting your home and property against flooding.

What's My Flood Risk?

Visit FEMA's Flood Map Service Center to locate your flood map to help determine your flood risk.

Contact Us | Site Map | Help | NFIP | Glossary | Email Updates
Last Updated: Tuesday, 27-Sep-2016, 1:47 PM (EDT)

500 C Street SW, Washington, D.C. 20472
Disaster Assistance: (800) 621-FEMA, TTY (800) 462-7585
U.S. Department of Homeland Security