Comment by jdmichal
2 days ago
> The storm surge goes up (and a whole bunch of water falls on top of it). The storm surge goes down. This isn't some river bursting it's banks.
FEMA has a flood rating specifically for exactly this situation: V. They have this because it carries additional hazards beyond normal flooding seen with storms.
> Coastal areas with a 1% or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26% chance of flooding over the life of a 30‐year mortgage.
And here's a video about researchers at the Oregon State University's Wave Lab studying this exact thing:
Once again, this sort of reddit-esque penchant for projecting general guidance and engineering standards into specific situations misses the mark.
Someone in a subdivision that's a few miles inland with a mangrove swamp between it and the ocean anyway has to care about New Orleans style flooding, not "what sea state is my picture window rated for" flooding.
Like there's a reason that Florida building code just says tie it down and call it good. It's just not necessary nor economically worthwhile to try and make structures shrug off the surf. Sure, literally on the coast type stuff will get rekt (most of that stuff is concrete now though) but the average modular home subdivision doesn't need special requirements above and beyond what it takes to shrug off the wind.
When it comes to wind loading the code is basically a fight between evil civil engineers who want the state jackboot to force you to buy their service and the hardware makers (Simpson and the like) who'd prefer you reference a conservatively pre-computed table and install that much of their hardware.
There are many reasons to shit on Florida but their building code is pretty top notch (and this makes it expensive but everything has tradeoffs).
I live in Tampa Bay, so I'm quite familiar. It's pretty rare to have a V rating, precisely for many of the reasons you mentioned. But, at the same time, handwaving it away as unimportant is also silly. It's an immensely more dangerous situation to be in flooding with moving water, as opposed to just rising water conditions. If nothing else, it's important to know for evacuation purposes. I would never willingly stay in a V-rated zone if there was a chance of storm surge. Then again, I didn't buy the V-rated house I wanted and instead found a house 40 feet above sea level, so maybe that's just my risk profile.
And I didn't disagree with you regarding building. You were wrong about storm surge always being static -- it mostly is, but importantly sometimes isn't. But you weren't wrong that there's not a lot to do about it. This is one of those situations where nature will win if it wants to. Best thing you can do is just not be there when it does.