To me it has all the hallmarks of a hoax. Or local urban legend. Has anyone else received this text?
UPDATE: Wow, the answer to that question was YES. See the comments. My daughter called me about half an hour after I posted this; she'd gotten the text three times and their entire office was wondering about the truth of the thing.
I'd tweeted the question (follow CathyBlogs) and my fellow blogger Angry White Boy (follow angry_white_boy on Twitter) was able to confirm that it was indeed a hoax; he sent me a link to a four-year-old story on MSNBC.com about the exactly same worded text that went around in Florida.
Certainly it's a good idea to use texting to let people know about emergencies; certainly also, that same method can be usurped for nefarious rumor mongering. At present, one must use one's own Spidey-sense to discern the difference. In the future. hopefully there'll be a better way.