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Flash
Flood Terminology
Flash
Flood Watch
- Indicates that flash flooding is a possibility in or close
to the watch area. Those in the affected area are urged to
be ready to take action if a flash flood warning is issued
or flooding is observed. These watches are issued for flooding
that is expected to occur within 6 hours after the heavy rains
have ended.
Flash Flood Warning
- A flood warning issued for life/property threatening flooding
that will occur within 6 hours. It could be issued for rural
or urban areas as well as for areas along the major rivers.
Very heavy rain in a short period of time can lead to flash
flooding, depending on local terrain, ground cover, degree
of urbanization, amount of man-made changes to the natural
river banks, and initial ground or river conditions. Dam breaks
or ice jams can also create flash flooding.
Flash Flood Statement
- A Flash Flood Statement is issued to inform the public about
current flash flood conditions. These statements usually contain
river stage information if major streams or rivers are involved.
Urban/Small Stream Flood Advisory
- Alerts the public to flooding, which is generally only an
inconvenience (not life-threatening) to those living in the
affected area. Issued when heavy rain will cause flooding
of streets and low-lying places in urban areas. Also used
if small rural or urban streams are expected to reach or exceed
bankfull. Some damage to homes or roads could occur.
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Flood
rescue efforts along the Choluteca River following Hurricane
Mitch.
NOAA Photo Library
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FLASH FLOODS AND FLOODS - THE AWESOME POWER!
In the United
States, an average of 100 people lose their lives in floods annually,
with flood damage averaging more than $2 billion. The Midwest's "Great
Flood of 1993" cost 48 lives and more than $12 billion. Flash
floods are the number one weather-related killer in the United States—2,200
deaths in Johnstown, Pennsylvania, May 31, 1889; 238 fatalities in
Rapid City, South Dakota, June 9, 1972; 140 killed in the Big Thompson
Canyon near Denver July 31, 1976; 26 dead in Shadyside, Ohio, June
14, 1990.
( - MORE - )
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The
NOAA National Weather Service operates 13 River Forecast Centers
that provide hydrological information for their region. An
interactive map displays current rivers conditions around the
United States and its territories. |
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Information
on flooding (when necessary) and routine hydrologic conditions
issued by NOAA National Weather Service Forecast Offices. |
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U.S.
River Conditions including observed stages, locations above
flood stage, levels compared to flood stage. |
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River Watch - Mississippi River Basin (Missouri
Basin, Upper Mississippi Basin, Ohio Basin, Arkansas Basin,
Lower Mississippi Basin) — Web site for quick access
to Mississippi mainstream river forecast information from
one central location. |
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The NOAA
Advanced Hydrologic Prediction Service provides
a Web-based suite of accurate and information-rich forecast
products that display the magnitude and uncertainty of occurrence
of floods or droughts—from hours to days and months in
advance. |
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Hydrologic
Outlooks - Information on excessive rainfall that
could lead to flash flooding, on areas where there is a risk
of significant river flooding and on water supply.
- Excessive
Rainfall Forecast
- Significant
River Flood Outlook
- Water
Supply Outlooks
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Flash
Flood - Preparations and Safety Guidelines - Flash
floods are the deadliest natural disaster in South Dakota. They
are caused by stationary or slow-moving thunderstorms that produce
heavy rain over a small area. The Black Hills are especially
vulnerable to flash floods, where steep terrain and narrow canyons
can funnel heavy rain into small creeks and dry ravines, turning
them into raging walls of water. Even on the prairie, normally-dry
draws and low spots can fill with rushing water during very
heavy rain. |
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Flash
Flood - Flash
floods can strike any time and any place with little or no warning.
In mountainous or flat terrain, distant rain may be channeled
into gullies and ravines, turning a quiet streamside campsite
or wash into a rampaging torrent in minutes.
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Flooding
- Of all the tricks in mother nature's weather bag, the deadliest
in the United States today is flooding and flash flooding. Over
the past 30 years, flood waters have claimed an annual toll
of nearly 140 lives in this country.
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Natural
Hazards - With Safety Rules
For Tornadoes, Hurricanes, Floods, Flash Floods, Thunderstorms/Lightning,
Winter Storms WATCH: Severe weather is possible within the designated
watch area. |
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NOAA National Weather
Service Low-Water Crossing Flood Safety Video
- The NWS, as a public service, provides
a video (at nominal cost) to disseminate motorist safety information.
The video points out the possibility of highway conditions occuring
as a result of flooding or flash flooding that are often the
cause of motorist fatalities and provides rules for safe operation
of vehicles under these conditions. |
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BILLION
DOLLAR WEATHER DISASTERS
The U.S. has sustained 54 weather-related disasters over a 23-year
period in which overall damages and costs reached or exceeded
$1 billion. Forty-five of these disasters occurred during the
1988-2002 period with total damages/costs of nearly $200 billion.
Seven occurred during 1998 alone—the most for any year
on record, though other years have recorded higher damage totals.
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River Forecast Centers - NOAA
National Weather Service
• Alaska/Pacific RFC
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Arkansas-Red Basin RFC
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California-Nevada RFC
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Colorado Basin RFC
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Lower Mississippi RFC
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Middle Atlantic RFC
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Missouri River Basin RFC
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Northcentral RFC
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Northeast RFC
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Northwest RFC
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Ohio RFC
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Southeast RFC
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West Gulf RFC |
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Hydrologic
Information Center - NOAA National Weather Service |
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NOAA
Weather Radio |
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NOAA
National Weather Organization Listing |
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