Flooding & Flash Floods
Prolonged rainfall over several days can cause a river or stream to overflow and flood the surrounding area. A flash flood from a broken dam or levee or after intense rainfall of one inch (or more) per hour often catches people unprepared. Regardless, the rule for being safe is simple: head for the high ground and stay away from the water. Even a shallow depth of fast-moving water produces more force than most people imagine. The most dangerous thing you can do is to try walking, swimming, or driving through such swift water. Still, you can take steps to prepare for these types of emergencies.
Flash flood waves, moving at incredible speeds, can roll boulders, tear out trees, destroy buildings and bridges, and scour out new channels. Killing walls of water can reach heights of 10 to 20 feet. You won't always have warning that these deadly, sudden floods are coming.
No area is immune to flash floods!
On small streams, especially near the headwaters of river basins, water levels may rise quickly in heavy rainstorms, and flash floods can begin before the rain stops falling. There is little time between detection of flood conditions and the arrival of the flood crest. Swift action is essential to protect life and property.
Flash floods also occur in or near mountainous area where torrential thunderstorm rains can quickly change a dry water curse or trickling little brook into raging treacherous torrents of water. Desert washes, particularly near mountains, can go from dry to flood stage within minutes as a result of thundershowers many miles away and out of sight or hearing of the flash flood site.
Urban flooding can occur in any terrain and is particularly aggravated by urbanization where natural cover has been removed by the construction of buildings, roads, and parking lots. Heavy rains can result in flash flooding, inundating cars and causing considerable damage to residential and industrial properties located along the steam channels. Streets can become rivers and basements, indoor swimming pools!
A flash flood watch is issued when flash flooding is possible within the designated watch area - be alert!
A flash flood warning is issued when a flash flood has been reported or is imminent - take necessary precautions.
In The Event of a Flood...
During the Flood
Avoid areas subject to sudden flooding.
Do not attempt to cross a flowing stream where water is above your knees.
Do not attempt to drive over a flooded road - you can be stranded or trapped. The depth of water is not always obvious.
If you're caught in the house, by sudden rising waters, move to the second floor and if necessary to the roof.
When outside the house remember floods are deceptive! Try and avoid flooded areas and don't attempt to walk through flood waters that are more than knee deep.
Turn off all utilities at the main power switch and close the main gas valve if evacuation appears necessary. Do not touch any electrical equipment unless it is in a dry area and your standing on a piece of dry wood whole wearing rubber gloves and rubber soled boots or shoes.
Fill bathtubs, sinks, and jugs with clean water in case regular supplies are contaminated. You can sanitize these items by first rinsing with bleach.
Board up windows or protect them with storm shutters or tape to prevent flying glass.
If It Is Safe To Evacuate By Car. . .
Stock the car with nonperishable foods, plastic container of water, blankets, first aid kit, flashlights, dry clothing and any special medication needed by your family.
Keep the gas tank at least half full. Since gas pumps will not be working in the electricity has been cut off.
If your car stalls in a flooded are, abandon it as soon as possible. Flood waters can rise rapidly and sweep a car (and its occupants) away. Many deaths have resulted from attempts to move stalled vehicles
After the Flood
Do not use fresh food that has come in contact with flood water.
Boil drinking water before using. Wells should be pumped out and the water tested for purity before drinking.
Seek necessary medical care at nearest hospital. Food, clothing, shelter, and first aid are available at shelters.
Do not visit disaster areas; your presence might hamper rescue and other emergency operations.
Do not handle live electrical equipment in wet areas; electrical equipment should be checked and dried before being returned to service.
Use flashlights, not lanterns or torches, to examine buildings, flammable may be inside.
Report broken utility lines to appropriate authorities.
Flood Safety Rules
Keep materials on hand such as sandbags, plywood, plastic sheeting, and lumber.
Keep first aid supplies at hand.
Keep your automobile fueled; if electric power is cut off, filling stations may not be able to operate pumps for several days.
Keep a stock of food that requires little cooking and no refrigeration; electric power may be interrupted keep a portable radio, emergency cooking equipment, lights and flashlights in working order.
Know your elevation above flood stage.
Know your evacuation route.
When you receive a flood warning.
Store drinking water in clean bathtubs and in various containers, before water service is interrupted.
If forced to leave your home and time permits move essential items to safe ground; fill fuel tanks to keep them from floating away; grease immovable machinery.
Move to a safe are before access is cut off by flood water.
Get out of the area subject to flooding. This includes dips, low spots, etc.
Avoid already flooded and high velocity flow areas. Do not attempt to cross a flowing stream on foot where water is above your knees
The road bed may not be intact under the water
If the vehicle stalls, abandon it immediately and seek higher ground - rapidly rising water may engulf the vehicle and its occupants and sweep them away.
Be especially cautious at night when it is harder to recognize flood dangers
Do not camp or park your vehicle along streams particularly during threatening conditions