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FLASH
FLOODS
What
is the difference between a Flood and a Flash Flood?
Flash flooding is a result of heavy localized rainfall such as that from
slow moving intense thunderstorms. Flash floods often result from small
creeks and streams overflowing during heavy rainfall. These floods often
become raging torrents of water which rip through river beds, city streets,
coastal sections and valleys or canyons, sweeping everything with them.
Flash flooding usually occurs within 6 hours of a heavy rain event.
Flash
floods are the number one weather related killer with around 140 deaths
recorded in the U.S. each year. .
On the other hand, the more long term "flood" is a natural and
inevitable part of life along our country's rivers. These floods occur
seasonally with general rains or torrential rains associated with tropical
storms, that later drain in river basins and fill them with an over- abundance
of water. General flooding occurs in urban areas and areas with poor drainage
after heavy rain.
Flash
Flood Safety Tips
In
hilly terrain, flash floods can strike with little or no advance warning.
Distant rain may be channeled into gullies and ravines, turning a quiet
stream into a rampaging torrent in minutes. Never camp on low ground next
to streams since a flash flood can catch you while you're asleep.
DO NOT DRIVE THROUGH FLOODED AREAS!
Even if it looks shallow enough to cross. The large majority of deaths
due to flash flooding occur with people driving through flooded areas.
Water only a foot deep can displace a 1500 lb. vehicle! Two feet of water
can easily carry most automobiles! Roads concealed by water may not be
intact.
Do not cross flowing stream on foot where water is above your ankles.
Do not allow children to play around streams, drainage ditches or viaducts,
storm drains, or other flooded areas!
Be especially cautious at night. It's harder to recognize water danger
then.
Don't try to outrace a flood on foot. If you see or hear it coming, move
to higher ground immediately.
Be familiar with the land features where you live, work, and play. It
may be in a low area , near a drainage ditch or small stream, or below
a dam. Be prepared!
Stay tuned to NOAA Weather Radio
for the latest statements, watches and warnings concerning heavy rain
and flash flooding in your area, report it to the National Weather Service.
Rugged
and often steep terrain only sets the stage for rapid storm water runoff
across the state. The biggest contributing factor is the summertime increase
in thunderstorms capable of producing heavy downpours in short periods
of time. People are often surprised at how quickly a normally dry arroyo
can become a raging torrent. Unlike the threat of large hail and tornadoes.
After
distant heavy rains, arroyos and streams downstream from the actual rain
area will carry the storm water runoff for many hours. If you see heavy
rain even many miles upstream from your area, remain alert for water in
the arroyos and across low water crossings for at least 6 to 12 hours.
You
can reduce the chances of becoming a flash flood victim by knowing how
to recognize these weather hazards as they develop and by observing the
following simple safety rules.
During
periods of thunderstorms, always remain alert to heavy rains in your immediate
area or upstream from your location. It does not have to be raining at
your location for flash flooding to occur.
Even 6 inches of fast-moving water can knock you off your feet, and a
depth of 2 feet will float your car! Never try to walk, swim, or drive
through such swift water. If you come upon flood waters, STOP! Turn around
and go another way. Most flash flood deaths occur in automobiles.
Plan your camping site carefully. Avoid stream areas where water can rush
downstream from distant rains.
Remember its harder to recognize dangerous flash flooding at night.
Keep children away from arroyos.
Waiting 15 to 30 minutes, or until high water recedes, is a simple safety
measure.
Are You Ready for a Flood or a Flash Flood?
Know
What to Expect
Know
your area's flood risk -- if unsure, call your local American Red Cross
chapter or emergency management office.
If it has been raining hard for several hours, or steadily raining for
several days, be alert to the possibility of a flood.
Listen to local radio or TV stations for flood information.
Floods Can Take several hours to days to develop
A
flood WATCH means a flood is possible in your area.
A flood WARNING means flooding is already occurring or will occur soon
in your area.
Prepare a Family Disaster Plan
Listen
to local radio or TV stations for flood information.
Check your homeowner's or renter's insurance to see if it covers flooding.
If not, find out how to get flood insurance.
Keep insurance policies, documents, and other valuables in a safe-deposit
box.
Assemble a Disaster Supplies Kit Containing:
First-aid
kit and essential medications
Canned food and can opener
At least three gallons of water per person (one gallon of water per person
for at least 3 days; often more is needed.)
Protective clothing, rainwear, and bedding or sleeping bags
Battery-powered radio, flashlight and extra batteries
Special items for infants, elderly or disabled family members
Written instructions for how to turn off gas and water if authorities
advise you to do so (Remember, you'll need a professional to turn them
back on.)
Identify where you could go if told to evacuate. Choose several places
. . . a friend's home in another town, a motel or a shelter.
When a flood WATCH is issued . . .
Move
your furniture and valuables to higher floors of your home.
Fill your car's gas tank, in case an evacuation notice is issued.
When a flood WARNING is issued . . .
Listen
to local radio and TV stations for information and advice. If told to
evacuate, do so as soon as possible.
When a flash flood WATCH is issued . . .
Be
alert to signs of flash flooding and be ready to evacuate on a moment's
notice.
When
a Flash Flood WARNING is issued..
Or
if you think it has already started, evacuate immediately. You may have
only seconds to escape. Act quickly!
Move to higher ground away from rivers, streams, creeks and storm drains.
Do not drive around barricades . . . they are there for your safety.
If your car stalls in rapidly rising waters, abandon it immediately and
climb to higher ground.
Plan and Get Ready
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 flood water provides
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. Have various
members of the family do each of the items on the checklist below. Then
hold a family meeting to discuss and finalize your Family Disaster Plan.
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