Damage Survey for Marion, Jasper and Poweshiek Counties for April 6th

The preliminary damage survey conducted by the National Weather Service Des Moines is below. 
Check back for damage and radar images that will be added in the near future.

...PRELIMINARY DAMAGE SURVEY RESULTS FOR MARION...JASPER AND
POWESHIEK COUNTIES...

THE STORM SURVEY INVESTIGATION IS STILL ONGOING AND SUBJECT TO
FURTHER COORDINATION WITH LOCAL EMERGENCY MANAGEMENT AGENCIES.

...DAMAGING STRAIGHT LINE WINDS AND LARGE HAIL...

THE FOLLOWING IS A PRELIMINARY ASSESSMENT FOR THE DAMAGE THAT
OCCURRED OVER MARION...JASPER AND POWESHIEK COUNTIES ON APRIL 6TH.

* EVENT DATE: APRIL 6TH

* EVENT TYPE: STRAIGHT LINE DAMAGING WINDS WITH EMBEDDED LARGE HAIL.

* PEAK WIND: 95 TO 105 MPH JUST WEST OF GRINNELL.

* AVERAGE PATH WIDTH: PEAK DAMAGE AREA AROUND 1 MILE WIDE WITH UP
TO 60 MPH EXPANDING OUT 2 TO 3 MILES ON EITHER SIDE OF PRIMARY
DAMAGE PATH.

* DISCUSSION/DAMAGE: A VERY STRONG THUNDERSTORM MOVED NORTHEAST
THROUGH MARION...JASPER AND INTO POWESHIEK COUNTY LATE TUESDAY
AFTERNOON. LARGE HAIL BROKE A FEW WINDOWS OUT OF HOMES ON THE
NORTHWEST SIDE OF KNOXVILLE. AN ISOLATED AREA OF STRONG WINDS
WAS LOCATED 5 MILES NORTHWEST OF PELLA. THE GREATEST DAMAGE IN
THIS LOCATION WAS 2 WALLS OF AN ATTACHED GARAGE BLOWN OUT. THE
GARAGE WALLS WERE ONLY ATTACHED WITH NAILS INTO THE CONCRETE
FOUNDATION. WIND COMING IN FROM THE OPEN GARAGE DOOR WAS ABLE TO
BLOW THE 2 WALLS OUT FROM BOTTOM TO TOP. THERE WAS ALSO SOME
HAIL DAMAGE WITH BROKEN WINDOWS AND HOLES IN VINYL SIDING. ONE
OPEN ENDED FARM SHED LOST A ROOF JUST DOWN THE ROAD...WHICH WAS
BLOWN APPROXIMATELY HALF A MILE. WIND SPEED ESTIMATES IN THIS
AREA ARE CONSISTENT WITH 75 TO 85 MPH STRAIGHT LINE WINDS.

THE STORM CONTINUED TO MOVE NORTH WITH LITTLE EVIDENCE OF STRONG
WIND DAMAGE...WITH THE EXCEPTION OF ONE BENT OVER STREET SIGN
AND DOWNED POWER POLES NEAR SULLY.

THE AREA ON THE WEST SIDE OF GRINNELL HAD THE MOST SIGNIFICANT
DAMAGE WITH THIS STORM. NUMEROUS VEHICLES WERE BLOWN OFF
INTERSTATE 80. LITTLE ADDITIONAL DAMAGE WAS NOTED OVER THIS
AREA HOWEVER...A VALLEY RUNNING THROUGH THE REGION MAY HAVE
LOCALLY ENHANCED WIND SPEEDS AS THE STORM APPROACHED THE
INTERSTATE.

NUMEROUS FARM OUT BUILDINGS SUFFERED SIGNIFICANT DAMAGE ON THE
WEST SIDE OF GRINNELL ALONG WITH DOWNED POWER LINES IN THE
REGION. SEVERAL HOUSES SUFFERED SIGNIFICANT VINYL SIDING AND
WINDOW DAMAGE. ANOTHER HOUSE HAD BOTH GARAGE DOORS BLOWN IN AND
THE WEST SIDE WALL REMOVED AND DEPOSITED NORTH OF THE LOCATION.
SEVERAL OTHER SOUTH FACING GARAGE DOORS WERE BLOWN IN AS
WELL...ALONG WITH SEVERAL TREES WHICH WERE SNAPPED OR UPROOTED
OVER THE REGION. THE DAMAGE ENDED 2 MILES NORTH OF GRINNELL.
DAMAGE INDICATORS SUGGEST DAMAGING STRAIGHT LINE WINDS OF 95 TO
105 MPH.


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