In my opinion, after Katrina, two big factors led to the quantity of foreclosures, and I believe neither will have nearly the same impact in Houston and surrounding area.
1) A substantial portion of New Orleans' population left and has never returned. That was a huge impact on the economy (retail, construction, services, etc.) and led to substantial job loss, likely the number one cause of foreclosure.
2) The tourism and convention business, a huge portion of New Orleans economy, effectively disappeared for a couple of years - again huge job losses. Houston has that as well, but is a much smaller percentage of our economy.
Unless we lose a substantial portion of our population (which I don't see likely at all), very few jobs will be lost in Houston, thus a very small number of foreclosures. Obviously the wild card is how widespread is the FEMA support going to be for those without flood insurance. Yes, there will be some foreclosures from that side, but I just don't see it being anywhere near that projection.