Public Information Statement
Issued by NWS Aberdeen, SD

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NOUS43 KABR 201118
PNSABR
SDZ003>011-015>023-033>037-045-048-051-202330-

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE ABERDEEN SD
618 AM CDT MON APR 20 2015 /518 AM MDT MON APR 20 2015/

...SOUTH DAKOTA SEVERE WEATHER AWARENESS WEEK...DAY ONE...
...THUNDERSTORMS...HAIL...WIND AND LIGHTNING...

THUNDERSTORMS...
AFFECT RELATIVELY SMALL AREAS WHEN COMPARED WITH MOST OTHER
STORMS. THE TYPICAL THUNDERSTORM IS 15 MILES IN DIAMETER AND LASTS
FOR 30 MINUTES. BUT DESPITE THIS SIZE...ALL THUNDERSTORMS ARE
DANGEROUS. SEVERE THUNDERSTORMS PRODUCE LARGE HAIL OR WINDS OF AT
LEAST 58 MPH. SOME WIND GUSTS CAN EXCEED 100 MPH AND PRODUCE
TORNADO-LIKE DAMAGE. MANY COMMUNITIES WILL SOUND THEIR OUTDOOR
SIRENS FOR VERY DAMAGING STRAIGHT-LINE WINDS. WHEN A SEVERE
THUNDERSTORM THREATENS...STAY INSIDE A STRONG STRUCTURE. MOBILE
HOME OCCUPANTS SHOULD GO TO A MORE PERMANENT STRUCTURE.

HAIL...
IS ANOTHER PRODUCT OF THUNDERSTORMS THAT ANNUALLY CAUSES NEARLY
ONE BILLION DOLLARS IN DAMAGE THROUGHOUT THE UNITED STATES. MANY
OF THE LOSSES ARE INCURRED BY FARMERS. THE MOST COMMON DIAMETER IS
PEA SIZE...BUT HAIL CAN BE AS LARGE AS GOLF BALLS AND BASEBALLS.
IN EXTREME CASES HAIL CAN REACH GRAPEFRUIT SIZE. LARGE HAIL STONES
FALL AT SPEEDS FASTER THAN 100 MPH AND HAVE BEEN KNOWN TO KILL
PEOPLE.

THE LARGEST HAIL STONE IN SOUTH DAKOTA LAST YEAR WAS 4.25 INCHES
OR THE SIZE OF A SOFTBALL. THE STONE FELL NEAR OGLALA IN SHANNON
COUNTY ON AUGUST 17.

THUNDERSTORM WINDS...
THUNDERSTORMS CAN PRODUCE STRONG WIND GUSTS. THESE STRAIGHT-LINE
WINDS HAVE BEEN KNOWN TO EXCEED 100 MILES PER HOUR. FOR THIS
REASON...YOU SHOULD TREAT SEVERE THUNDERSTORMS JUST AS YOU WOULD
TORNADOES. MOVE TO AN APPROPRIATE SHELTER IF IN THE PATH OF THE
STORM.

THE STRONG OUT RUSH OF WIND FROM A THUNDERSTORM IS OFTEN CALLED A
DOWNBURST. ONE OF THE PRIMARY CAUSES IS RAIN-COOLED AIR...WHICH
ACCELERATES RAPIDLY DOWNWARD...PRODUCING A POTENTIALLY DAMAGING
GUST OF WIND.

STRONG DOWNBURSTS ARE OFTEN MISTAKEN FOR TORNADOES. THEY CAN
PRODUCE EXTENSIVE DAMAGE AND ARE OFTEN ACCOMPANIED BY A ROARING
SOUND SIMILAR TO THAT OF A TORNADO. DOWNBURSTS CAN EASILY OVERTURN
MOBILE HOMES...TEAR ROOFS OFF HOUSES...AND TOPPLE TREES. PEOPLE
WHO ARE CAMPING ARE ESPECIALLY VULNERABLE...DUE TO TREES TOPPLING
ONTO THEIR CAMP SITES.

THE HIGHEST WIND GUST RECORDED LAST YEAR IN SOUTH DAKOTA WAS 96
MPH WHICH OCCURRED IN SIOUX FALLS ON JUNE 16.

LIGHTNING...
EVERY THUNDERSTORM PRODUCES LIGHTNING...WHICH ON A NATIONAL
BASIS...KILLS MORE PEOPLE THAN TORNADOES IN A GIVEN YEAR.
LIGHTNING KILLS AROUND 100 AMERICANS ANNUALLY...WITH ABOUT 300
INJURIES. THE MAJORITY OF FATALITIES OCCUR DURING LEISURE
ACTIVITIES... LIKE SOFTBALL OR BASEBALL...FISHING AND CAMPING.

THE FOLLOWING ARE SOME SAFETY TIPS...

   1.  ALL THUNDERSTORMS PRODUCE LIGHTNING. IT IS SURPRISING THAT
       MANY PEOPLE ARE NOT AWARE OF THIS.

   2.  GET INSIDE A BUILDING OR ENCLOSED VEHICLE.
       MANY FATALITIES OCCUR WHEN THE WARNING SIGNS ARE IGNORED.

   3.  IF CAUGHT IN AN OPEN AREA WITH LIGHTNING ALL
       AROUND...CROUCH DOWN IMMEDIATELY! PUT YOUR HANDS BEHIND
       YOUR HEAD...BUT DO NOT LIE DOWN ON THE GROUND.

   4.  DO NOT USE A CORDED TELEPHONE OR ELECTRICAL APPLIANCE. A
       NEARBY LIGHTNING STRIKE CAN TRAVEL THROUGH THE PHONE OR
       POWER LINES...RIGHT INTO THE HOME.

   5.  AVOID SEEKING SHELTER BENEATH LONE TREES.

MYTHS AND FACTS...

MYTH...IF IT IS NOT RAINING...THERE IS NO DANGER FROM LIGHTNING.
FACT...LIGHTNING OFTEN STRIKES AWAY FROM HEAVY RAINFALL AND MAY
       OCCUR AS FAR AS 10 MILES AWAY FROM ANY RAINFALL.

MYTH...RUBBER SOLES OF SHOES...OR RUBBER TIRES ON A CAR WILL
       PROTECT YOU FROM BEING INJURED BY LIGHTNING.
FACT...RUBBER PROVIDES NO PROTECTION FROM LIGHTNING.  HOWEVER...
       THE STEEL FRAME OF A HARD-TOPPED VEHICLE PROVIDES
       INCREASED PROTECTION IF YOU ARE NOT TOUCHING METAL.

MYTH...PEOPLE STRUCK BY LIGHTNING CARRY AN ELECTRICAL CHARGE
       AND SHOULD NOT BE TOUCHED.
FACT...LIGHTNING-STRIKE VICTIMS CARRY NO ELECTRICAL CHARGE AND
       SHOULD BE ATTENDED TO IMMEDIATELY.

MYTH...HEAT LIGHTING OCCURS AFTER VERY HOT SUMMER DAYS AND POSES
       NO THREAT.
FACT...WHAT IS REFERRED TO AS HEAT LIGHTNING IS ACTUALLY
       LIGHTNING FROM A THUNDERSTORM TOO FAR AWAY FOR THUNDER
       TO BE HEARD. HOWEVER...THE STORM MAY BE MOVING IN YOUR
       DIRECTION.


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