Understanding the Risks of Flooding and Flash Flooding

May 22, 2013  |    |  Weather Radios

You know what they say… When it rains, it pours. And then it can flood. Understanding the risk for flooding and flash flooding in your area is just as important to severe weather safety as planning for other emergency situations.

Flooding is defined as a temporary and general condition where normally dry areas are overwhelmed by water or mudflow. Hurricanes, severe thunderstorms, heavy rainfall, snowmelt, ice jams, spring thaw, levee breaches, obstructed drainage systems and more can cause flooding, even in areas that are not prone to it. According to FloodSmart.gov, those in moderate to low risk flooding areas file almost 20% of flood insurance claims.

Areas that haven’t flooded in the past are not immune to flooding later. Rain amounts, changes in the land due to development and a number of other factors impact risk of flooding. Flood maps are regularly updated to reflect changes in an area’s risk of flooding. You can check whether or not your area is scheduled for updating or has been updated by entering your zip code at the Flood Map Update Schedule.

Flash flooding on the other hand seemingly happens in a flash. Flash floods appear within six hours of the event that caused them. Those events include slow moving or intense rain storms, dam or levee breaches, quick snowmelt or ice jams. Flash flooding commonly occurs in, but isn’t exclusive to, areas near streams and rivers. These waterways can quickly rise from a few inches to several feet high even though the event happened far upstream.

The sudden nature of a flash flood means you won’t always receive advanced warning that a potentially deadly flood is coming.  Anytime you’ll be near streams and rivers, like when you’re camping, hiking, etc., or you live in an area at risk for flash flooding, you should be prepared. It takes just a few adjustments to waterproof your emergency preparedness kit.

If you’re driving, remember the National Weather Service’s popular motto: “Turn around, don’t drown.” NOAA reports nearly half of all fatalities in a flash flood occur in cars. A mere six inches of water can cause loss of control in a car and a foot of water will make most vehicles float. Rushing water’s depth and speed are easy to underestimate. At night, it is even more difficult to tell if a road is passable or washed out.

When camping, hiking or engaged in any other outdoor activity near a river or stream, check to see if the area is a flood zone and if a warning system is in place that alerts for flooding possibilities. If you’re on foot, never risk trying to cross a shallow stream. Only six inches of moving water can knock you off your feet. Take along a portable NOAA weather alert radio since systems can fail and cell phone service can be unreliable in these areas.