July 8, 2000. In just a period of hours, up to five inches of rain fell across Northeast Wisconsin as thunderstorms moved across the region. Storm sewers were unable to keep up with the deluge. City streets flooded. Water flowed up from sewers into basements. The flash flood caused hundreds of thousands of dollars in damage.
Floods are more than an inconvenience, they are the leading cause of death from thunderstorms. Most flood deaths are the result of flash floods, and nearly half of flash flood deaths are automobile-related.
Flash floods occur within a few minutes or hours of excessive rainfall, a dam or levee burst, or a release of water held by an ice jam. There will not always be a warning that these sudden, deadly floods are coming, and it may not even be raining in your area-- but runoff from a faraway thunderstorm could head your way.
Several factors contribute to flash flooding. The two key elements are the intensity of the rainfall and how long the rain lasts. Soil conditions, ground cover, and landscape features also play an important role.
Watches and Warnings
Flash Flood or Flood Watch Flash flooding or flooding is possible within the designated area. Be alert to signs of rising water and be ready to evacuate at a moment's notice. Tune to WBAY-TV for updates on conditions and forecasts.
Flash Flood or Flood Warning Flash flooding or flooding has been reported or is imminent. When a warning is issued for your area, or the moment you realize yourself that a flash flood is imminent, act quickly to save yourself.
Urban and Small Stream Advisory Flooding of small streams, streets, and low-lying areas, such as railroad underpasses and storm drains, is occurring.
Flood Flood or Flood Statement Follow-up information from the National Weather Service regarding a flash flood or flood event.
If advised to evacate, do so IMMEDIATELY. Move to a safe area before access is cut off by flood water.
Get to higher ground. Get out of areas subject to flooding. This includes dips, low spots, washes, etc.
Avoid areas of flowing water. The water can rise quickly. Six inches of fast-moving water can knock you off your feet. A depth of two feet will lift a car and make it float. NEVER try to walk, swim, or drive through such swift water. STOP, turn around, and find another route.
If your vehicle stalls, leave it immediately and seek higher ground. Rapidly rising water may engulf the vehicle and sweep it-- and its occupants-- away.
Be especially cautious at night when it's harder to recognize flood dangers. The reflection of still water in your headlights will give you no indication of the water's true depth, and the road bed may be washed out under the water.
After a Flood
If fresh food has come in contact with flood waters, throw it out.
Contact your local public works department about water safety. Boil drinking water before using. Wells should be pumped out and the water tested for purity before drinking.
Electrical equipment should be checked and dried before being returned to service.
Use flashlights-- not lanterns, torches, or matches-- to examine buildings. Flammables may be inside.
Report broken utility lines to appropriate authorities.
Before a Flood
Know your flood risk and elevation about flood stage. Do your local streams or rivers flood easily?
Install check valves in building sewer traps to prevent flood water from backing up into the drains of your home.
Homeowners' and renters' policies rarely cover flooding. Contact your insurance agency about getting flood insurance.
Store drinking water in clean bathtubs and various containers if water service may be interrupted.
Keep a stock of food that requires little cooking and no refrigeration in case electric power is interrupted.
Keep your automobile fueled. If electric power is cut off, gas stations may not be able to operate pumps.