Floods & "Flash Floods"
Flash floods are the #1 weather-related killer in the U.S.
Floods begin when soil and vegetation cannot absorb falling rain or melting snow, and when water runs off the land in such quantities that it cannot be carried away quickly enough in normal stream channels or cannot be retained in natural ponds and man-made reservoirs.
Some floods develop slowly, sometimes over a period of days; however, flash floods can develop quickly within a few minutes or hours of heavy rainstorms or a dam or levee failure. It's important to be aware of flood hazards no matter where you live, but especially if you live in a low-lying area, in a densely populated area, near water or downstream from a dam.
- Flash floods occur within a few minutes or hours of excessive rainfall or a dam failure. Flooding is a longer-term event and may last a week or more.
- Most flash flooding is caused by (1) slow-moving thunderstorms, (2) thunder-storms repeatedly moving over the same area or (3) heavy rains from hurricanes and tropical storms.
- Flash floods can roll boulders, tear out trees, and destroy buildings and bridges.
- Densely populated areas have a high risk for flash floods. The construction of buildings, highways, driveways, and parking lots increases runoff by reducing the amount of rain absorbed by the ground.
- Water can erode the road bed creating unsafe driving conditions.
- Many flash floods occur at night when flooded roads are hard to see.
- 2 feet of water will float your car, truck or SUV!!! 6 inches of fast-moving floodwater can knock you off your feet.
- Nearly half of all flash flood fatalities are auto related. If your car stalls, leave it and seek higher ground, if you can do so safely.
- Underpasses can fill rapidly with water, while the adjacent roadway remains clear. Driving into a flooded underpass can quickly put you in 5-6 feet of water.
Understanding Weather Reports & Alerts...
Flash Flood Or Flood Watch:
Flash flooding or flooding is possible within the designated WATCH area-be alert.
Flash Flood Or Flood Warning:
Flash flooding or flooding has been reported or is imminent-take necessary precautions at once.
Urban & Small Stream Advisory:
Flooding of small streams, streets, and low-lying areas, such as railroad underpasses and urban storm drains is occurring.
Flash Flood Or Flood Statement:
Follow-up information regarding a flash flood/flood event.
Flood Safety Tips...
- Never try to walk, swim, or drive through swift-moving floodwater. If you must walk in a flooded area, walk where the water is not moving. Remember, 2 feet of water will float your vehicle and 6 inches of fast moving floodwater can knock you off your feet.
- If you come upon floodwaters, STOP, TURN AROUND AND GO ANOTHER WAY!!
- Do not attempt to drive through a flooded road.
- If your car stalls, leave it and seek higher ground, if you can do so safely.
- Stay informed about the storm and possible flooding by listening to your NOAA weather radio, commercial radio or television.
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