Lynnville-Malcom Tornado Survey Complete

During the evening of Sunday September 30, 2007 two tornadoes struck portions of Marion, Jasper and Poweshiek
Counties. The first tornado produced EF0 to EF2 damage along its track and was rated EF2
on the Enhanced Fujita Scale with maximum winds of 125 mph. The track was 22 miles in length
from 4 miles northeast of Pella to 1 mile north of Interstate 80, 2 miles west of Malcom.
Much of the track was three to five tenths of a mile wide, but as wide as seven tenths of a mile
at times.

The map below shows the paths of both tornadoes. Click on the map for a larger and
clearer view.

 Image showing tornado tracks



The image below shows National Weather Service Doppler Radar imagery as the EF2 damage was occurring
at around 625 pm CDT. The bright red and green colors show the tornado circulation, greens with motion toward
the radar and reds away from the radar. Click on the image for a larger and clearer view.

Image depicting storm relative motion radar data


The tornado was rated EF2 due to damage at the Co-Line Manufacturing plant and also at a home across
County Road T38. This was a south facing wall at the plant that blew in allowing a section of the roof to
fail. The second image, courtesy of John McLaughlin at IowaHelicopter.com, shows extensive portions of the
northwest and south roof removed. Peak winds through this stretch were estimated to be around 125 mph.

EF2 Damage at Co-Line Manufacturing
Co-Line Manufacturing from above
 
Across the road, damage occurred to a house that was also rated high end EF2. The attached garage and
house addition were destroyed, while the original section of the house only had partial roof
damage. The second image, taken by Chris Maiers ABC5 Des Moines, shows a pickup truck that
was blown out of a second demolished garage and rolled to its resting point.





The tornado continued to produce damage across Mahaska County breaking several wooden power
poles with more EF2 damage. Another house that suffered EF1 damage in the form of a
destroyed garage had also been hit 10 years ago in 1997. The tornado weakened and then crossed
Interstate 80 before ending.

The second, shorter and weaker tornado was 5 miles in length and rated EF1 on the Enhanced Fujita
Scale. The track began just south of Highway 6, 2.75 miles northwest of Malcom with a maximum
width of 150 yards narrowing to 25-50 yards. The storm hit a farmstead just east of 110th street
producing EF1 damage with speeds just under 100 mph.

Some of this information was provided by John McLaughlin and IowaHelecopter.com. The National
Weather Service appreciates this partnership in providing aerial survey information.

For reference, the Enhanced Fujita Tornado Scale classifies tornadoes into the following
categories.
  • EF0 - 65 to 85 mph
  • EF1 - 86 to 110 mph
  • EF2 - 111 to 135 mph
  • EF3 - 136 to 165 mph
  • EF4 - 166 to 200 mph
  • EF5 - Winds > 200 mph


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