Survey Says Five Tornadoes in NE Iowa - ABC5 News Des Moines, IA

Survey Says Five Tornadoes in NE Iowa

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by Phil Prazan

pprazan@myabc5.com

@PhilPrazan

A crew from the National Weather Service in Johnston left Thursday morning to survey the damage and bring back a first look at the storms. 

 
Using GPS trackers to map all the damage points, the National Weather Service team was able to map out the path of the Tornado, crossing the northwest side of Belmond.

Five tornadoes have been confirmed: two EF0s,one EF1,  one EF2 and the largest by Belmond clocked in as an EF3 that struck a path 8 miles long and 200 yards wide.

The survey team has certain criteria when they investigate damage: scientific formulas that calculate how much force it would take to damage certain objects like trees and houses.

So by plotting certain damage points back on the map, they get a good idea of where the tornado went and how powerful it was.
 
"Anything we can find, if we find a board stuck into a house we know that it at least takes 100-110 mph winds to do that," explained Roger Vachalek from the National Weather Service.

This improves forecasting which leads to life saving information.  The EF scale that they measure tornados by ranks certain wind speeds of the storm.  So to be a EF3 tornado, it had to have speeds more 136 miles per hour.

That twister northwest of Belmond was this year's strongest tornado in Iowa.

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