National Weather Service meteorologist Steve Haines tells the Star that damage done to the Regions Bank Building Sunday night was caused by straight-line winds, rather than a tornado. "We had a team out evaluating the damage (in Marion County), and they couldn't find any signs of 'rotations' that would indicate a tornado," Haines said.
AI is no meteorologist, but we must take issue with a lack of evidence of rotation. Let's start with the fact that the building sustained damage on three sides, the south, west and north sides as the storm approached from the west-southwest. The building's window curtail wall on two sides of the building was bowed outward, indicating a vacuum-like effect. Debris from the building could be found in four directions from the building, some of which landed blocks away. At least some of the damage to the Star building, which is northwest of the Regions building, appeared to come from debris from the Regions building, like the projectile which pierced the ceiling of editor Barb Henry's office on the top floor. A final signature of a twister was the isolated nature of the damage. Other than the Star building, the other surrounding buildings, including those within the immediate block of the Regions building sustained no damage whatsoever. This would be consistent with a funnel cloud briefly touching down and then lifting it up and remaining aloft.
My home in Lockerbie is about four blocks northeast of the Regions building. Whatever winds hit my neighborhood during the storm didn't approach what hit the Regions building, and my neighborhood is populated with homes and buildings over a hundred years old, which sustained absolutely no damage. But we're not the experts so this one will be recorded as straight-line wind damage in the official record book.
6 comments:
I live a couple of miles east of downtown - the winds knocked down a decrepit unoccupied house on my street. The winds also arrived very suddenly and blew open my loosely-fastened front and back door.
I lean toward the tornado explanation because of the noise: it was the first time I can recall ever hearing the fabled 'sound of a locomotive passing above' - true, the sound was not that incredibly loud but definitely reminiscent...
fox 59 is reporting that the damage was likely caused by the bernoulli effect.
I thought about the wind tunnel effect as well, but I can't imagine how many times over the several decades that building has been standing there that a storm would have come through which would have generated winds powered by wind tunneling with similar or even greater strength. There was something different about the winds which hit the building just right to cause damage on 3 sides--I think it can only be explained by a twister. The main impact areas were on the corners, but there were other windows much further away from the corners which were also knocked out from flying debris. That indicates a rotating action pulling objects away from the building and then slamming them back against the building.
Gary, I lived in Lockerbie in one of the townhomes on the west side of East Street for 11 years. I cannot guess the number of times I went out into our cozy backyard garden and tried to measure if the INB Tower was so tall that it would crush my house in a big tornado (or, heck, straight line winds). I had visions of huddling in the basement, like good Midwesterners, only to have shards of curtain walls and glass and metal poke through our poured concrete basement wall. In 11 years, I was never convinced that I was safe from that hulk.
TDW discussed the same thing after the storm. I always was fearful of pointy structural members. But TDW's downtown lawn was strewn with sensitive legal papers!
It never occured to me that I would be showered by legal files rather than pointy objects. I don't live in that townhouse anymore, but I guess I feel better anyway.
There used to be this myth that tornados never struck the downtowns of major cities because of the pressure changes from the taller buildings. We've seen tornados strike the downtowns of Nashville and Dallas in recent years.
in IUPUI, We actually did some wind modeling to understand effect of the building topology in extreme wind conditions. You might wanna check some results in the following link. This building is exposed to higher wind speed due to upstream buildings. Lower stories are kind of protected from high winds but upper stories are exposed to even higher winds than the actual wind speed.
http://www.engr.iupui.edu/cfdlab/research/projects/EnviCFD/WInd_Effect_files/ExtremeWind_AIrQuality_INGIS07_Workshop-1.pdf
Post a Comment