Just to give an idea of how powerful a hurricane is, the MOAB has about 9 tons of explosives. Assuming it is TNT (the explosive I have some numbers for), that would be about 3.8 x 10^10 joules of energy. An average hurricane releases about 5.2 x 10^19 joules per day. So the MOAB has as much energy as 63 microseconds of an average hurricane. Rita is far more powerful than an average hurricane.
http://www.aoml.noaa.gov/hrd/tcfaq/D7.html for hurricane energy info.