Dam Break

Dam failure or levee breeches can occur with little warning. Intense storms may produce a flood in a few hours or even minutes for upstream locations. Flash floods occur within six hours of the beginning of heavy rainfall, and dam failure may occur within hours of the first signs of breaching. Other failures and breeches can take much longer to occur, from days to weeks, as a result of debris jams.

What to Do Before a Dam Failure
Knowing your risk, making sure an Emergency Action Plan (EAP) is in place.
Evacuating when directed by emergency response officials are the most important steps you can take to staying safe from a dam failure.
 
Ways to Plan Ahead
Know your risk. Do you live downstream from a dam? Is the dam a high-hazard or significant-hazard potential dam?
To find out, contact your State or Local Government emergency management agency. Once you determine that you live downstream from a high-hazard or significant-hazard potential dam and find out who manages the dam, see if a current EAP is in place for the dam. An EAP is a formal document that identifies potential emergency conditions at a dam and specifies preplanned actions to be followed to reduce property damage and loss of life. An EAP specifies actions the dam authority should take to take care of problems at the dam. It also includes steps to assist the dam managersowner in issuing early warning and notification messages to responsible downstream emergency management authorities of the emergency.
If there is a dam failure or an imminent dam failure and you need to evacuate, know your evacuation route and get out of harm’s way. In general, evacuation planning and implementation are the responsibility of the state and local officials responsible for your safety. However, there may be situations where recreational facilities, campgrounds, or residences are located below a dam and local authorities will not be able to issue a timely warning. In this case, the dam authority should coordinate with local emergency management officials to determine who will warn you and in what priority.