Lew Rockwell sees Katrina and the damage done, and points a finger at the public sector:
Mother Nature can be cruel, but even at her worst, she is no match for government. It was the glorified public sector, the one we are always told is protecting us, that is responsible for this. And though our public servants and a sycophantic media will do their darn best to present this calamity as an act of nature, it was not and is not. Katrina came and went with far less damage than anyone expected. It was the failure of the public infrastructure and the response to it that brought down civilization.
Tyler Cowen suggests several possible libertarian approaches to levee privatization here, while himself arguing that "many levees are genuine public goods, and should receive government support."