PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY
415 PM CDT MON MAY 24 1999

...UPDATED INFORMATION ON THE HARRISON COUNTY IOWA TORNADOES...

THE FOLLOWING IS UPDATED INFORMATION ON THE HARRISON COUNTY TORNADOES OF MAY 16TH.  THIS INFORMATION IS BASED ON AERIAL AND GROUND SURVEYS OF THE STORM DAMAGE CONDUCTED ON MAY 17TH BY THE NATIONAL WEATHER SERVICE.

MISSOURI VALLEY-LOGAN TORNADO (F3)- THIS TORNADO BEGAN AT THE IOWA WELCOME CENTER....3 MILES NORTHEAST OF MISSOURI VALLEY.  A ROOF WAS DAMAGED AT THE WELCOME CENTER AND A ROOF WAS BLOWN OFF ONE OF THE HISTORICAL BUILDINGS NEXT TO THE VISITOR CENTER.  THE TORNADO TRACKED NORTHEAST CAUSING TREE DAMAGE.  A STEEL TRUSS BRIDGE CROSSING THE BOYER RIVER WAS DEMOLISHED.  THE TORNADO NEXT CAUSED DAMAGE TO A FARM ONE MILE NORTHEAST OF THE DESTROYED BRIDGE.  THE TORNADO CONTINUED ON ITS NORTHEAST COURSE AND WIDENED TO NEARLY 1/4 MILE AND SNAPPED OR UPROOTED NUMEROUS TREES ALONG THE WAY.  THE TORNADO NEXT FLATTENED A HOME ON OVERTON AVENUE AND DAMAGED ROOFS AND BARNS OF TWO OTHER
RESIDENCES. IT WAS ALSO IN THIS AREA THAT THERE WERE TWO FATALITIES. THE TORNADO...NOW AT F3 STRENGTH...DESTROYED SEVERAL HOMES ON 270TH STREET.  THERE WERE ALSO NUMEROUS FLIPPED OR SMASHED VEHICLES AROUND THIS AREA.  A GRADUATION PARTY WAS HELD IN ONE OF THE RESIDENCES. CONTINUING NORTHEAST...THE TORNADO FLATTENED ANOTHER HOME ON READING TRAIL.  THE TORNADO THEN WEAKENED AS IT DAMAGED ANOTHER COUPLE OF FARMS AND FINALLY DISSIPATED.  THE TOTAL PATH LENGTH OF THE TORNADO WAS 7.5 MILES.  ALTHOUGH SOME HOMES WERE FLATTENED...MANY OF THEM HAD NO REBAR CONNECTIONS TO THE FOUNDATION.  THUS...THE TORNADO RATING WAS GIVEN AN F3 ON THE FUJITA SCALE.  AN F3 HAS WINDS BETWEEN 158 TO 206 MPH.

CALHOUN-MAGNOLIA TORNADO (F3)-  THIS TORNADO...SMALLER THAN THE
MISSOURI VALLEY-LOGAN ONE...STARTED 4 MILES NORTH OF MISSOURI VALLEY NEAR THE SMALL COMMUNITY OF CALHOUN.  BECAUSE OF THE SLOW MOVEMENT OF THE PARENT THUNDERSTORM...THE TORNADO HAD AN UNUSUAL TRACK.  THE TORNADO STARTED IN A FIELD WEST OF HIGHWAY 183 AND MOVED NORTH FOR 1/4 MILE.  THE TORNADO STOPPED AND THEN HEADED EAST AND THEN NORTHEAST...FOLLOWING THE WILLOW CREEK VALLEY.  FOR A MAJORITY OF ITS LIFE...THE TORNADO WAS IN OPEN FIELDS.  AT APPROXIMATELY 3 MILES NORTHEAST OF CALHOUN...THE TORNADO STRUCK A FARMSTEAD DESTROYING A BARN AND SOME OUTBUILDINGS.  THE TORNADO THEN STARTED MOVING NORTH-NORTHEAST AND STRUCK A FARMSTEAD...DESTROYING A HOME AND SEVERAL VEHICLES.  THE TORNADO NEXT BEGAN MAKING A LARGE TURN...FIRST TO THE 
NORTH...AND FINALLY TO THE WEST WHERE IT FINALLY DISSIPATED. THE TOTAL PATH LENGTH OF THIS TORNADO WAS 6.2 MILES AND THE LARGEST WIDTH WAS 200 YARDS.

A MAP AND PHOTOGRAPHS CAN BE SEEN AT THE VALLEY NATIONAL WEATHER
SERVICE WEB SITE AT WWW.CRH.NOAA.GOV/OAX/

BRIAN E. SMITH
WARNING COORDINATION METEOROLOGIST

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY
300 PM CDT MAY 18 1999

...INFORMATION ON HARRISON COUNTY IOWA TORNADOES...

THE NATIONAL WEATHER SERVICE CONDUCTED AN AERIAL AND GROUND SURVEY OF THE TORNADOES THAT STRUCK HARRISON COUNTY IOWA.  HERE IS SOME BASIC INFORMATION ON THOSE STORMS.

LOGAN TORNADO      F3   1/4 MILE WIDE   7 MILES LONG
MAGNOLIA TORNADO   F3   200 YARDS WIDE  7 MILES LONG

BRIAN E. SMITH
WARNING COORDINATION METEOROLOGIST