April 09, 2011 – Northwest Iowa Chase

Started the day off by analyzing model data, etc as usual.  I knew today had potential, just didn’t realize how much.  A potent weather situation was setting up across the state, especially across NW / N Iowa.  A warm front was progged to lift across the state, based from a low in NE/SD.  As this day was well advertised, a plethora of chasers were headed for the same area.

Determined my target to be Denison, IA.  I’ve staged in Denison many a time and have yet to be disappointed.  Warm temps aloft (the cap) were a major concern, so I delayed my departure from home until almost 1pm CST.  Spotter Network was becoming the usual honeycomb of chasers all targeting NE Nebraska / NW Iowa.

Arrived in the area about 2:30-3:00ish.  Topped off the ol fuel tank (ouch!) and grabbed a bite to eat.  Then I did a chaser’s favorite past time. Sitting and waiting.  After what seemed like an eternity, the SPC finally issued a MCD for the area; stating a Tornado Watch was imminent.

Initiation finally started near Columbus, Nebraska.  Multiple chasers raced towards the storm.  I positioned myself just North of Ute, IA.  Initial storm motion had it moving N/NE but I had a gut feeling it would change, and it did!  Finally has the storm took a right turn and moved into Iowa, the 1st tornado warning of the evening was issued.

Since I had a county road handy, I moved west to take a sneak peak.  A wall cloud was evident and that was about it at the time.  Moving back east towards my original spot north of Ute, the storm spawned a couple of weak funnels.  Cutting my way thru the traffic, I made it back to my spot just in time to see the monster of a tornado that went on to hit the town of Mapleton, Iowa.  The thing was huge!  Darkness was quickly approaching and light was becoming an issue in trying to see anything.  I zigg-zagged further E/NE and caught a few more tornadoes.  The wall cloud was very persistent.

Not wanting to chase at night and being darn far from home, I decided to call it a night and head back to the barn.

Thoughts:

Glad to see NW IA didn’t disappoint me again!  I was also proud of the many chasers that stopped and gave aid to countless Iowans after their lives were turned upside down by numerous tornadoes.  We usually hear so much negatives about chasers, it’s nice to hear the good.

12-14 injuries were reported in Mapleton, IA with the most serious being a broken leg.  No fatalities!  I chaulk this up the early warning they had.  Thanks again to my fellow chasers for helping with the ground truthing and keeping people safe.  See we aren’t all about the glory and drama! 😉

Preliminary damage assessment reveals that the Mapleton, IA tornado was 3/4 of a mile wide and did low end EF-3 damage.  Numerous other tornadoes also were confirmed in NW IA.  I’ll post more information as it becomes available about them.

Photos:

[flickrset id=”72157626469508248″ thumbnail=”small” photos=”” overlay=”true” size=”medium”]

 

Storm Reports for April 09, 2011 from the SPC


Prelim Damage Assessment for Mapleton, IA

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
308 PM CDT SUN APR 10 2011

...TORNADO DAMAGE IN MONONA COUNTY IOWA INCLUDING MAPLETON...

THIS IS A PRELIMINARY MESSAGE. ADDITIONAL DETAILS MAY BE PROVIDED
LATER.

A SURVEY TEAM DID A DAMAGE ASSESSMENT OF THE TORNADO THAT MOVED
ACROSS PARTS OF MONONA COUNTY IOWA SATURDAY EVENING APRIL 9 2011.
THIS INCLUDED THE TOWN OF MAPLETON.

SO FAR...A PATH LENGTH OF AROUND 3.5 MILES HAS BEEN DETERMINED. THE
MAXIMUM WIDTH OF THE TORNADO WAS 0.75 MILES. THE WORST DAMAGE WAS
NOTED TO BE IN THE LOWER END OF THE EF3 CATEGORY.

MONONA COUNTY EMERGENCY MANAGEMENT ESTIMATED 12 TO 14 INJURIES...THE
WORST OF WHICH WAS A BROKEN LEG.

EF3 WIND DAMAGE IS CAUSED BY WINDS ESTIMATED AT 136 TO 165 MPH.

Link to full article on KOAX’s website regarding the Mapleton, Iowa tornado.

 

Perlim Damage Assessment for Sac County, Iowa

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
456 PM CDT SUN APR 10 2011

...PRELIMINARY DAMAGE SURVEY RESULTS FOR SAC COUNTY...

THE STORM SURVEY INVESTIGATION IS STILL ONGOING AND SUBJECT TO
FURTHER COORDINATION WITH LOCAL EMERGENCY MANAGEMENT AGENCIES.
THIS SURVEY WILL BE UPDATED ON MONDAY WITH ADDITIONAL INFORMATION.

...SURVEY FOR SAC COUNTY, IOWA...

THE FOLLOWING IS A PRELIMINARY ASSESSMENT FOR THE DAMAGE THAT
OCCURRED OVER SAC COUNTY ON APRIL 10, 2011.

* EVENT DATE: APRIL 10, 2011

* TORNADO NUMBER 1

* ESTIMATED START TIME: UNKNOWN

* EVENT TYPE: (EF2) TORNADO

* EVENT LOCATION: TORNADO BEGAN 3 NE ODEBOLT AND ENDED 1 NE EARLY

* PEAK WIND: 132 MPH

* AVERAGE PATH WIDTH: 1/2 MILE WIDE

* PATH LENGTH: 9 MILES LONG

* INJURIES: UNKNOWN

* FATALITIES: NONE KNOWN

* DISCUSSION/DAMAGE: MULTIPLE HOMES DAMAGED

* TORNADO NUMBER 2

* ESTIMATED START TIME: UNKNOWN

* EVENT TYPE: (EF3) TORNADO

* EVENT LOCATION: TORNADO BEGAN 1 N ODEBOLT AND ENDED 6 NW EARLY

* PEAK WIND: 140 MPH

* AVERAGE PATH WIDTH: 1 MILE WIDE

* PATH LENGTH: 11 MILES LONG

* INJURIES: UNKNOWN

* FATALITIES: NONE KNOWN

* DISCUSSION/DAMAGE: MULTIPLE HOMES DAMAGED OR DESTROYED

* TORNADO NUMBER 3

* ESTIMATED START TIME: UNKNOWN

* EVENT TYPE: (EF2) TORNADO

* EVENT LOCATION: TORNADO BEGAN 1 SW NEMAHA AND ENDED
  APPROXIMATELY 3 SE NEWELL

* PEAK WIND: 125 MPH

* AVERAGE PATH WIDTH: 1/2 MILE WIDE

* PATH LENGTH: 8 MILES LONG FOR THIS SEGMENT...ANOTHER TEAM IS
  SURVEYING A PORTION OF THE SAME STORM THROUGH ANOTHER AREA.

* INJURIES: UNKNOWN

* FATALITIES: NONE KNOWN

* DISCUSSION/DAMAGE: HIGH TENSION WIRES DOWN...MULTIPLE HOMES
  DAMAGED OR DESTROYED...HOG OUTBUILDINGS DOWN.

* TORNADO NUMBER 4

* ESTIMATED START TIME: UNKNOWN

* EVENT TYPE: (EF2) TORNADO

* EVENT LOCATION: TORNADO BEGAN 2 NW NEMAHA AND ENDED APPROXIMATELY
  AT THE BUENA VISTA...SAC...POCAHONTAS...CALHOUN COUNTY LINE.

* PEAK WIND: 125 MPH

* AVERAGE PATH WIDTH: 1/2 MILE WIDE

* PATH LENGTH: 12 MILES LONG

* INJURIES: UNKNOWN

* FATALITIES: NONE KNOWN

* DISCUSSION/DAMAGE: MULTIPLE HOMES DAMAGED OR
  DESTROYED...OUTBUILDINGS DOWN

&&

FOR REFERENCE...THE ENHANCED FUJITA TORNADO SCALE CLASSIFIES
TORNADOES INTO THE FOLLOWING CATEGORIES:

EF0...WIND SPEEDS 65 TO 85 MPH.
EF1...WIND SPEEDS 86 TO 110 MPH.
EF2...WIND SPEEDS 111 TO 135 MPH.
EF3...WIND SPEEDS 136 TO 165 MPH.
EF4...WIND SPEEDS 166 TO 200 MPH.
EF5...WIND SPEEDS GREATER THAN 200 MPH.

Link to full article on KDMX’s website with photo’s and maps.

This entry was posted in 2011 Chases.