I was looking at houses a while back (in CA), and there were a couple in the $400k range, while everything else was at least double. They were closest to the San Pablo Bay and in the first level of inundation on this map.
I have a couple of friends who bought close to sea level in the area. One got out, and the other is dealing with underground corrosion due to groundwater salinity. If he doesn't get out, I expect him to get stuck upside-down on his mortgage.
Then there's insurance. I've noticed that, in many situations, they're becoming the driving force for relocation, ahead of individual self interest. You can't borrow money for a house without insurance, and they're 100% in control of when they choose to pull out. They don't get stuck with the property in the end.
What will happen to these communities is insurance prices will skyrocket, or become unavailable. The government will step in and insure the houses, but not for new buyers. The banks get their money back, but the homeowners will have unsaleable property, or nothing at the end of 30 years.
What hasn't happened yet is for the market to adjust in areas that don't see inundation until 2060. Those are some of the scariest situations, because all it'll take is rumor, and suddenly whole neighborhoods will be stuck losing value.