Weather Week

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
800 AM CDT MON APR 2 2011

...TODAY BEGINS SEVERE WEATHER AWARENESS WEEK IN IOWA...

GOVERNOR TERRY BRANSTAD...THE IOWA HOMELAND SECURITY AND EMERGENCY
MANAGEMENT DIVISION...AND THE NATIONAL WEATHER SERVICE HAVE
DESIGNATED THE WEEK OF APRIL 2 TO APRIL 6 AS SEVERE WEATHER
AWARENESS WEEK IN IOWA.  EACH MORNING THIS WEEK...THE NATIONAL
WEATHER SERVICE IN DES MOINES WILL ISSUE A PUBLIC INFORMATION
STATEMENT FOCUSING ON A DIFFERENT ITEM EACH DAY.  TOPICS THIS YEAR
INCLUDES THE FOLLOWING...

     MONDAY...FLASH FLOODING
     TUESDAY...WARNING RECEPTION
     WEDNESDAY...TORNADOES
     THURSDAY...SEVERE THUNDERSTORMS
     FRIDAY...FAMILY PREPAREDNESS

ATTENTION MEDIA...IN ORDER FOR SEVERE WEATHER AWARENESS WEEK TO BE
EFFECTIVE...MEDIA COVERAGE IS CRITICAL.  PLEASE USE THE INFORMATION
IN THE PUBLIC INFORMATION STATEMENTS IN YOUR NEWS PROGRAMS TO HELP
PROMOTE SEVERE WEATHER SAFETY.  WE ALSO ENCOURAGE MEDIA INTERVIEWS.
PLEASE CONTACT JEFF JOHNSON OR THE SENIOR METEOROGIST IF YOU ARE
INTERESTED.

CHECK OUT THE NEW NATIONAL WEATHER SERVICE DES MOINES PREPAREDNESS
PAGE.  IT IS FULL OF NEW SEVERE WEATHER PREPAREDNESS INFORMATION AND
IT CAN BE FOUND ON THE NATIONAL WEATHER SERVICE DES MOINES
WEBSITE...UNDER PREPAREDNESS ON THE LEFT HAND SIDE.

TODAY/S TOPIC IS FLASH FLOODING.

EACH YEAR...MORE DEATHS OCCUR DUE TO FLOODING THAN FROM ANY OTHER
THUNDERSTORM RELATED HAZARD...RESULTING IN MORE THAN 140 FATALITIES
EACH YEAR. MOST FLASH FLOODS ARE CAUSED BY SLOW MOVING
THUNDERSTORMS...THUNDERSTORMS THAT REDEVELOP OVER THE SAME AREA...OR
HEAVY RAINS FROM TROPICAL STORMS AND HURRICANES. THESE FLOODS CAN
DEVELOP WITHIN MINUTES OR HOURS DEPENDING ON THE INTENSITY AND
DURATION OF THE RAIN...THE TOPOGRAPHY...SOIL CONDITIONS...AND GROUND
COVER.

A FLASH FLOOD IS A RAPID RISE OF WATER ALONG A STREAM OR LOW-LYING
URBAN AREA. FLASH FLOODS CAN ROLL BOULDERS...TEAR OUT
TREES...DESTROY BUILDINGS AND BRIDGES... AND SCOUR OUT NEW CHANNELS.
RAPIDLY RISING WATER CAN REACH HEIGHTS OF 30 FEET OR MORE.

A FLASH FLOOD WATCH IS ISSUED BY THE NATIONAL WEATHER SERVICE TO
INDICATE CURRENT OR DEVELOPING HYDROLOGIC CONDITIONS THAT ARE
FAVORABLE FOR FLASH FLOODING IN AND CLOSE TO THE WATCH AREA. THE
OCCURRENCE OF FLOODING IS NEITHER CERTAIN NOR IMMINENT. THOSE IN THE
WATCH AREA SHOULD BE ALERT FOR FLOODING.

A FLASH FLOOD WARNING MEANS NATIONAL WEATHER SERVICE METEOROLOGISTS
HAVE DETERMINED THAT FLASH FLOODING IS OCCURRING OR IMMINENT. THOSE
IN THE WARNING AREA SHOULD TAKE THE NECESSARY PRECAUTIONS AT ONCE.

ALMOST HALF OF ALL FLASH FLOOD FATALITIES OCCUR IN VEHICLES. MANY
PEOPLE DO NOT REALIZE TWO FEET OF WATER ON A BRIDGE OR HIGHWAY CAN
FLOAT MOST VEHICLES. IF THE WATER IS MOVING RAPIDLY...THE CAR OR
TRUCK CAN BE SWEPT OFF THE BRIDGE AND INTO THE CREEK OR DOWNSTREAM
WITH THE FLOWING WATER. WATER CAN ERODE THE ROAD BED...CREATING
UNSAFE DRIVING CONDITIONS. UNDERPASSES CAN FILL RAPIDLY WITH
WATER...WHILE THE ADJACENT ROADWAY REMAINS CLEAR. DRIVING INTO A
FLOODED UNDERPASS CAN QUICKLY PUT YOU IN FIVE TO SIX FEET OF WATER.
MANY FLASH FLOODS OCCUR AT NIGHT WHEN FLOODED ROADS ARE DIFFICULT TO
SEE.

WHEN YOU APPROACH A FLOODED ROAD...TURN AROUND...DON/T DROWN!

FLASH FLOOD MYTH VS. FACT...

MYTH...FLASH FLOODS ONLY OCCUR IN THE EASTERN UNITED STATES.
FACT...FLASH FLOODS HAVE AND CAN OCCUR IN ALL 50 STATES...INCLUDING
ALASKA AND HAWAII.

MYTH...FLASH FLOODS OCCUR ONLY ALONG FLOWING STREAMS.
FACT...FLASH FLOODS CAN OCCUR IN DRY CREEK BEDS AND URBAN AREAS
WHERE NO STREAMS ARE PRESENT.

MYTH...FLASH FLOODS OCCUR MAINLY IN THE LATE AFTERNOON AND EVENING.
FACT...FLASH FLOODS CAN OCCUR AT ANY TIME OF DAY... MANY FLASH
FLOODS OCCUR AT NIGHT...TOO.

MYTH...LARGER VEHICLES...SUCH AS SUVS AND PICKUPS...ARE SAFE TO
DRIVE THROUGH FLOOD WATERS.
FACT...TWO FEET OF RUSHING WATER CAN CARRY AWAY MOST VEHICLES...
INCLUDING SUVS AND PICKUPS.

MYTH...HOMEOWNER INSURANCE POLICIES COVER FLOODING.
FACT...UNFORTUNATELY...MANY HOMEOWNERS DO NOT FIND OUT UNTIL IT IS
TOO LATE THAT THEIR POLICES DO NOT COVER FLOODING. CONTACT YOUR
INSURANCE COMPANY OR AGENT ABOUT FLOOD INSURANCE.

HERE ARE SOME FLOOD SAFETY TIPS:

BEFORE A FLOOD...
KNOW THE COUNTY IN WHICH YOU LIVE AND THE NAMES OF NEARBY MAJOR
CITIES. CHECK THE WEATHER FORECAST BEFORE LEAVING TO BE OUTDOORS FOR
EXTENDED PERIODS. WATCH FOR SIGNS OF APPROACHING STORMS.
MONITOR THE NOAA WEATHER RADIO OR YOUR FAVORITE NEWS SOURCE FOR
VITAL WEATHER RELATED INFORMATION. DO NOT CAMP OR PARK YOUR VEHICLE
ALONG STREAMS AND WASHES... PARTICULARLY DURING THREATENING
CONDITIONS.

IF FLOODING OCCURS...
GET TO HIGHER GROUND.
GET OUT OF AREAS SUBJECT TO FLOODING. THIS INCLUDES DIPS...LOW
SPOTS...CANYONS... WASHES...ETC. AVOID AREAS ALREADY FLOODED...
ESPECIALLY IF THE WATER IS FLOWING FAST. DO NOT ATTEMPT TO CROSS
FLOWING STREAMS.
ROAD BEDS MAY BE WASHED OUT UNDER FLOOD WATERS. NEVER DRIVE THROUGH
FLOODED ROADWAYS. DO NOT ALLOW CHILDREN TO PLAY NEAR HIGH WATER...
STORM DRAINS OR DITCHES. HIDDEN DANGERS COULD LIE BENEATH THE WATER.
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE FLOOD
DANGERS.

JEFF JOHNSON
WARNING AND COORDINATION METEOROLOGIST
NATIONAL WEATHER SERVICE DES MOINES IA
WWW.WEATHER.GOV/DESMOINES