We got a direct hit on our house in Palm Beach County, Florida from
Hurricane Frances. Hours and hours of high winds gusting well over 100
mph, See my photo gallery at:

http://www.truetex.com/frances

It was a novel and challenging experience, especially as an engineer and
inveterate do-it-yourselfer.

I learned quite a bit about the mechanics of wind damage and what works
to stand up to it. Even a good mechanical intuition is likely to be
incorrect about these things. I thought I'd pass along some of the
lessons I learned.

First, the pressure from hurricane force winds is only on the order of a
few pounds per square foot. This I learned by perusing _Marks_ handbook
during the long night of winds when I ran out of reading material.
Heavy debris does not leap up into the air and fly around. Structural
problems are due to the wind catching things in a sail-like or a can-
opener-like manner, and collecting and concentrating the few lbs/sq-ft
force onto critical fastenings.

Before the storm came I was all concerned to get shutters on the
windows, and fussing with a shortage of fasteners drained by a panicked
populace. But it turns out you don't need plywood fastened with 1/2-
inch lag bolts over your windows. A 4x4 foot sheet, say, 16 sq ft, is
only going to experience at most about 100 lbs of pull-off force. It is
not like there is some horrific suction that wants to tear things off.
My aluminum channel strut reinforcements were way overdone [metalworking
content!].

I was worried about my 10' x 7' garage doors that were 1970s pre-
hurricane-code construction. I bought pieces of 10' SuperStrut to
reinforce and anchor them to the concrete floor, but didn't have time
for that metalworking project before the winds hit. During the highest
winds, these experienced at most a few hundred pounds of force, which
certainly made them slowly bow in and out a few inches with the slowly
rising/falling gusts, but not fail, rather like a crude windspeed
indicator. I actually wedged myself in between the garage door and the
back of my Jeep, and bonded with the breath of the beast as she huffed
and puffed. It was like a giant hand was outside pushing and relaxing a
few times each minute.

While we tried to clear our 0.85 acres of loose stuff before the storm,
there were a few things left around. It was odd how light little things
didn't get moved by the wind, while healthy, well-rooted 60-foot trees
were knocked down. For example, I had a 3-foot assembly of 3/4" PVC
pipe leaning against an outside wall, directly facing the worst winds,
and it didn't even get tipped over. Small scraps of plywood stayed
where they fell from cutting.

Second, the handy guy in the neighborhood with the tools and know-how is
very popular in a calamity. Having the materials, skills, and chutzpah
to improvise in a crisis is a shining moment.

Third, while many neighbors had all their roof shingles stripped, we
lost none except the corners of a few on the peak row. I wasn't the
owner when the last re-roof was done 12 years ago, but it appears to me
that the heavier shingles made all the difference, especially
considering the minimal increment in cost. I believe the peak shingles
were broken by the way the slope of the roof must have caught the wind
and highly concentrated the force with an airfoil effect.

Fourth, securing a household in the absence of time and retail hardware
is like being on a boat in the middle of the ocean. No one is going to
help you, there is no place to go for supplies, and the mechanical
problems are extreme and puzzling in a way you never have dealt with.
Everything depends on your own wits and what you have on hand.