Odds of Getting In
Breaking into the field is going to depend partly on location. If you're in Mayberry, where Barnie Fife is second-in-command at the police department, then odds are the local emergency management requirements will be in easy reach. Other areas will have hundreds of applicants responding to one opening, though. If lack of experience is getting in your way, you can explore one of the first-responder options (Red Cross, county and city reserve programs, Community Emergency Response Team, etc.).
Fortunately (or unfortunately, depending on how you look at it), disasters will never go away.