Wednesday, June 15, 2016

6/15/2016 Twister County Damage Survey (Non EF-5 Example)

Statistics:

Max Wind Speed: 156 MPH
Cities Impacted: Elwood
Time On Ground: Approximately 10-12 minutes
Damage Rating: Mid EF-3 (See second image)
This tornado started just outside Elwood, looking like it was going to barely graze the outskirts as an EF-0 to early EF-1. However, around the time the tornado hit 100 MPH, the tornado quickly turned towards the southwest side of town. The tornado became an EF-2 as it entered Elwood, then continued onward. Just before the tornado exited the town, it became an EF-3 and continued to grow to 156 MPH. The tornado left the town of Elwood, heading for an open field, where it weakened and eventually dissipated.

Images:


Image of the target area, southwest Elwood.
Sample damage survey image.
Frequently Asked Question: "Why is the house with the clean slab not EF-5 damage?"
Good question! The house with the (nearly) cleaned slab was actually a blue house, which is a very weak house. During my chase of this tornado, I discovered an interesting behavior with the stability of each house. Notice how the green house with EF-3 damage had the same damage as the blue house with EF-2 damage. This is because on the stability scale (which has to be learned in Twister County), EF-3 damage to a green house looks the same as EF-2 damage to a blue house and EF-4 damage to a brown house (though it would have to be a low EF-4 instead of a mid EF-4). Plus, the tornado never hit 200 MPH, therefore no EF-5 damage could have been present.

Using this knowledge of the stability scale and how it works, future damage assessments in Twister County (of mine, at least) are able to be more accurately represented. Eventually, I will create an EF Scale for myself based on Twister County. If the owner asks, I will release it to the public after I am finished, but it will take many tornado chases to gather enough information to create an accurate representation.