How does one become a freelance stringer?

Ok so, I am storm chaser of sorts in southern calif. Most of the year its sunny, but on rare occasions there is severe weathering, flooding, severe thunderstorms, etc. And for fun I chase them, take photos, and video, then I send it to the news and they show it most of the time. A couple years back there was a large fire spawned by lightning, and I was on the phone with the news, giving them up to minute reports, with video and photos, they were airing all my media, on breaking news. So I'm wondering can't I get paid for this? How do I get paid?