I read on several threads that FEMA was ordered to stay out by local NO authorities because their safety could not be guaranteed.
LA Game and Fish had organized a flotilla of boats to get people off rooftops - I saw some of them on camera on FOX, maybe 50-75 little john boats. They were turned back because they were fired upon.
You can't in good conscience ask folks who are rescuers, not soldiers, or even just ordinary people trying to help, to go in under fire.