Engineer: Winds, not surge packed Katrina's punch

Engineer: Winds, not surge packed Katrina's punch: "When Hurricane Katrina's storm surge came ashore in Jackson County, there was nothing left to destroy; that was done by the storm's 125 to 150 mph winds that hit the area two to four hours before the surge, an engineer studying the storm damage said."

I know this is a touchy subject for a lot of people out there in the middle of a wind vs. water debate with their insurance companies. I realize that I can't possibly make a lot of friends by harping on this issue...

It's true that I am not a forensic engineer who is being paid by several coast residents (as the article states) to try to find some way to blame anything but the storm surge for the destruction on our coast. However, unlike Mr. Biddy, I just happened to have been here when Katrina made landfall.

Now you would think with our peculiar experience here during Hurricane Katrina -- i.e. not only were we here for the storm from start to finish, but we also did not spend that time trapped in a dark attic with no view of what was happening outside -- that folks would be breaking down our door asking for a true first-hand account of what conditions were like in their area.

But that's not going to happen.

From the article: " National Weather Service records show that 125-mph winds from Katrina hit the Coast long before the high water came ashore." Let's assume for a moment that there really were 125 mph sustained winds pummeling the shore prior to Katrina's landfall. Those winds fall into the Saffir-Simpson scale under a Category Three hurricane (as Katrina has now been classified). From the scale itself - such winds would likely cause the following destruction:

"Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Damage to shrubbery and trees with foliage blown off trees and large trees blown down. Mobile homes and poorly constructed signs are destroyed. "

Er... does that describe the damage our engineer is trying to assess? Not quite.

(By the way - the same scale also warns of storm surge damage and rising water in this way: "Low-lying escape routes are cut by rising water 3-5 hours before arrival of the center of the hurricane. Flooding near the coast destroys smaller structures with larger structures damaged by battering from floating debris. Terrain continuously lower than 5 ft above mean sea level may be flooded inland 8 miles (13 km) or more." I do think the part about the water rising 3-5 hours before the arrival of the eye is incredibly interesting after surviving a storm which brought water into my house 4 hours after the eye came ashore 95 miles from here.... But that's something for future blogging....)

Of course all of this is assuming that there really were 125 mph sustained winds here in Pascagoula -- and that this information was collected by the National Weather Service.

But, according to the National Weather Service Forecast Office Baton Rouge/New Orleans, LA's Post-Tropical Cyclone Report for Hurricane Katrina the data reads as follows:

ALL ASOS DATA IS INCOMPLETE DUE TO POWER INTERUPTION PRIOR TO PEAK
WIND AND MIN PRESSURE OCCURRENCE.

ASOS....2 MINUTE SUSTAINED WINDS

PASCAGOULA PQL ....DATA INCOMPLETE SUSTAINED 080/38 KT 0953 UTC
PEAK 090/44 KT 0933 UTC

For my non-nautical readers, 38 knots translates to roughly 45 miles per hour. A sustained 45 mile per hour wind is defined as a 'fresh gale'. We can safely say that the recorded sustained winds at this point in the storm were between 'fresh gale' and 'strong gale'. A strong gale can cause slight structural damage -- such as what occured at our house before the water arrived (i.e. sections of vinyl siding blown off, sections of asphalt shingles blown off).

The peak wind gusts of 44 knots can be translated to roughly 51 mph.

Further on down in our NWSFO report - we find another reference to Pascagoula:

EMERGENCY OPERATIONS CENTERS...PEAK GUST OBSERVED BEFORE WIND
EQUIPMENT WAS BLOWN DOWN.

PASCAGOULA -JACKSON COUNTY MS EOC -
PEAK 108 KT

A 108 knot gust (approximately just over 120 mph) is pretty formidable.. but is what it
says -- a gust. This is not a sustained wind.

And so this is where our engineer friend got his data about 125 mph winds ravaging the coastline before the storm surge ever made it here.

One tree almost went down in our yard in Katrina's winds. It's the same tree on the north side of our house that goes down every time we have a storm. It fell over in Tropical Storm Bill, it fell over after a thunderstorm that same year, it fell over when Hurricane Ivan passed to our east, and it fell over in Tropical Storm Cindy. We staked it up in four directions in preparation for Hurricane Katrina. Not one stake pulled up in Katrina's winds.. although the tree was listing a bit. We were very proud of ourselves for that one... Until the surge came in and knocked it over in a matter of minutes. We watched our stakes float away. We watched the surge take over two other trees in our front yard and four trees in the backyard. We watched it wash a tree over in our neighbor's front yard... We watched it uproot an enormous live oak at the end of the cul-de-sac. We even watched it straighten our own little live oak that had been leaning badly toward the south since Hurricane Ivan.

I understand that the NWS data is incomplete... I know that we experienced quite a few hurricane-force gusts here -- enough to rumble through the house and shake the walls. But we experienced nothing that would have been capable of causing such widespread devastation in that storm... until the water came.

But still -- it's only our experience.. and we couldn't be everywhere at once.

I have a thousand questions of my own for the ace engineers out there... I am interested in finding out how these things happen. Someone explain the myriad of collapsed houses with roofs still totally intact -- not so much as a ruffled shingle... gutters still neatly attached... Just a roof sitting on the slab where the house used to be.. How does the wind so delicately avoid the most fragile features of the house while in the process of ripping it off its foundation? And as my mother pointed out in her blog once -- what about the trees? Why did this catastrophic wind spare the trees? Why so many standing next to utter ruin -- complete with branches and green leaves? (Until a few weeks later when the salt water started to take its toll, that is.)

And how about a question I'm not sure an expert like Ted Biddy can answer... What the HECK was I doing laughing, joking, and trying to make biscuits while Katrina's catastrophic winds raged outside our window? Shouldn't I have had the good sense to go crawl under a mattress and pray for mercy? That didn't happen til later... and we needed to be on the other side of the mattress....

So here I am. A witness. A witness like my husband and my mother and our kids. But who cares what we have to say? We're amateur witnesses. Ted Biddy, on the otherhand... is a professional.

(For more info - check out Mr. Biddy's website at: http://www.forensicengineer-expertwitness.com/)