Hurricane Katrina Straight Line Wind Field Study
Southwinds Golf Course Area near Ocean Springs, Mississippi
I found a number of straight-line paths Southwinds Golf Course. We walked east, when the straight-line wind pattern moved due south. (See picture 2.) We changed directions and walked between two homes that were damaged during Hurricane Katrina. (See picture 3.)
As we walked down Barbaretta Drive, the damage to the houses increased. We turning right on Dismuke at the corner of Crescent Shore Drive the two houses near the corner were both very damaged. A tree was down between the houses, showing the wind came from the south. (See picture 5.) Turned down Crescent Shore Drive, we found two trees on the left side lot had been splintered. (See picture 6.) The rest of the lot was being cleaned up, the house was gone, but a tree on the west side of the lot was down, showing the wind came from the west. (See picture 7.) Across the street and down one lot, we found another tree that was splintered. (See picture 8.) Starting at these three points, eight of ten houses were gone; only one was in the process of being rebuilt. The trees surrounding this area were going in all different directions, in a classic starburst pattern. (See picture 9.) Four houses that were built on concrete pillars were gone but the pillars now were pointing in different directions. (See picture 10 and 11.) The houses must have crashed straight downward as the air dropped down, blowing the foundation pillars into a starburst pattern, i.e., going in different directions.
I had found the touchdown area. This was a very strong microburst area.I hoped no one was in these houses when the downburst hit because that would have crashed into them. The trees in the wooded area surrounding this area showed starburst patterns to them, going in different directions. (See picture 12 and 15.) The straight-line tree pattern led me to this place and I felt I was in a graveyard. Later, I found two additional touchdown areas that affected this area with possible tornadoes, mini-swirls, gustnadoes, microbursts and straight-line winds
In the Plains States and other high tornado areas, people believe that they were hit by a tornado but in reality they were hit with straight-line winds or a microburst touchdown area. If the victims stated that the tornado was noisy, like a train, they most likely were hit by straight-line winds traveling out of a microburst. In the latter instance the wind would be pushing things over as it is traveling along at a high speed at, or near the ground level. The destruction is often at an angle away from the general wind pattern hit at that time. Or if the victims stated the tornado came straight down, it is most likely that there was downward flow of air. Often microburst touchdown areas just missed the person telling the story.
Many people say the difference between a tornado and straight-line winds is that straight-line winds do not have a vortex that extends upward into the atmosphere. Dr. Ted Fujita in his books points out that descending air is a vortex downward. The touchdown area he called, microburst,& is very damaging as well as the straight-line winds coming out at all directions from the touchdown area.
I realize that downbursts are considered rare events during hurricanes because the winds would push the air enough horizontally to give that air a soft landing as the air above is descending downward. During hurricanes, most people would say that the rain was flying sideways. This horizontal wind would give the falling atmospheric air a soft landing. Dr. Ted Fujitas studies indicated that a microburst diminished and stopped when a horizontal wind speed reaches about 35 meters per second. This would lead one to believe that all downbursts would not leave a major impact on the impacted area. But consider this: most anemometers recorded top winds speed at about 50 mile per hour before they stopped functioning. Hurricane Katrinas unstable cloud structure reached over 6 miles into the atmosphere. When the vortex descended downward, if the horizontal wind speed was low at that location, the touchdown area would have a hard landing. It would flatten the trees and houses at Ascot Point on the Southwinds Golf Course. The straight-line winds coming out of the touchdown area would travel in all directions and could be traveling at 120 to160 miles per hour. I found evidence of downburst in surrounding areas but did not have the time to do a detailed study. (See pictures 16, 26 and 27.)
In summation, the scientific method investigation into why Hurricane Katrinas damage was so large led me to a better understanding of what happens during hurricanes. My studies led me to understand the devastating power of downburst and the immense importance for understanding how it affects houses.
As with any scientific investigation, my opinions, hypotheses and conclusions are subject to study, questions, and revisions as more information is gathered.