See my question below: what wave force is the transmission infrastructure rated for? "Flooding" seems like the wrong term- hurricane-driven waves will bring a lot of force to bear on anything solid and attached to the ground.

Gustav managed to damage high voltage lines even at a smaller size and being a Cat 2 storm at landfall. Ike is much bigger and probably a Cat 2/3 at landfall.

But I would expect high voltage transmission lines to be built to hurricane tolerances in places like Texas

I follow you. I would expect people NOT to build their homes on the very beach of Texas, due to .... you know.BTW which insurance company do they use?

Yes, however, the substations and other equipment are still on the ground. I've seen flood remediation work on flooded homes. Basically, ALL the electrical stuff that gets wet has to be replaced. The water carries dirt and grit that settles into everything, and makes future use of the electrical equipment dodgy.

When the ground turns to soup due to flooding, its hard to keep things standing upright even in 50mph winds.

Stupid is as stupid does

One way grid sucking is old school , Why not contribute
to the stability of the grid instead of cratering it. Electrons flow to where the customers & dollars are.
Lot's of fumes to run these plants on AND help support LOCAL grid infrastructure.
But no, we have to pay for stranded costs,
Market now demands the cleanest electrons . FIT's (Feed In Terrifs) needed, but often not possible even on the mega-watt level, must import kwH from hundreds of miles away. In the early 80's we did auto transfer (grid drop )for safety and obvious reasons on Hydrocarbon complexes. We had to have a battery room for transfer to keep the brains up, but today required battery's could fit in a Yukon (or even Prius) instead of bunkers. So the up issue should not be the grid. But it may be to dated
designs