Rhino,While many of those are good orgs from what I know of them, and definitely fill needed roles, I do not believe they are what the founders intended by the 2nd Amendment.
GRANTED. - As I've been asked in emails & phone messages, "I cannot show up to help but can I do anything??", I've listed a few of the many volunteer agencies that "interested people" can support. - Every little bit helps.
Otoh, IF you can "show up" at the disaster area (and can support yourself while there - We CANNOT & WILL NOT support you.), don't wait to be asked. = When you arrive, simply ask, "What can I do??" = You will be given a needed task that otherwise either would NOT get done or would be "put off" until later.
(I remember one 60YO+ man, who was disabled, who appeared with his PU after HUGO & said, "Is there anything that you need?? - I have a good PU." = Being told that disposable diapers & "little kids clothes" were BADLY NEEDED & unavailable, Mr. Finch went home to TN, got together with his wife, started calling friends & "like magic" trucks of disposable diapers & children's clothes just APPEARED, w/i 48 hours. = THANKS to "The Knoxville crowd".)
ADDENDA: During the last major HOUSTON FLOOD, a man from New Orleans came to the "ad-hoc" R&R Center & offered his help "for anything that you need". - Told that we needed more help "picking people out of trees & off rooftops", he drove to a dealer north of Cleveland, TX, bought a 16 foot boat/motor/trailer & came back that same afternoon.
(It was later learned that he & his family had been rescued during KATRINA.)