Last week, I sent the local National Weather Service office a link to my Michigan City wind damage photos, which I described as a possible “smoking gun” proving that a tornado hit the area. I just got a reply from an NWS forecaster, who thanked me for the photos but begged to differ with my conclusion, basically concluding that lexicon was right. I quote from the forecaster’s e-mail:
Thanks for your time and energy in bringing this to our attention. We are always looking for photos and video of weather related damage and anything else weather related.
As a matter of fact, while we were on our damage survey, we did see the bleachers. They were rolled several times.
In other surveys I have done over the last dozen years in Indiana, Michigan and Ohio…I have seen many rolled into pretzels just like this set. The funny thing is, these type bleachers tend to get airborne in 90 to 100 mph winds…whether they are associated with a tornado or with damaging straight line winds.
One thing is for sure…the Michigan City to Westville areas experienced a horrific wind storm. This storm is a rarity. One the area will likely not see again in a lifetime (I hope!). Our job, at the NWS, now is to decide what caused the damage as best as humanly possible. You know, we had a Tornado Warning out for the storm…so us classifying it as wind damage gives us a miss on our statistics. This negatively effects our funding and reputation. Frankly, as a scientist, I don’t care about the verification statistics when we are doing damage surveys…we are trying to determine what caused the damage based on the facts and our knowledge.
When determining what caused wind damage we look at many things. We are looking for damage that converges (is a result of suction) or that which occurred with outflow (winds blowing out of the thunderstorm). To determine this we interview eye witnesses, meticulously examine surface at the damage, look at the damage from aircraft, also we review the radar signatures and examine the atmosphere at the time. We attempt to put all the clues together, like a crime scene, and figure out what happened.
All the clues continue to point to a widespread “straight line” wind event. This event was extremely uncommon and best relate it to a hurricane. There was 30 miles by 30 miles damage. The biggest tornado on record is near a mile wide…therefore all the damage that occurred could not have been caused by “a” tornado. There could have been small tornadoes embedded in the hurricane type winds, but we could not find sufficient evidence to substantiate them. By the way, we are still looking for any other damage information we can get, including still pictures and movies of the storm. (I would love to be able to give us a hit on the Tornado Warning!)
Interesting, very interesting.