After the Japan earthquake and tsunami and nuclear plant crisis, it’s hard to think about more disaster, especially close to home.

But last night some 130 tornadoes tore a swath through the South, killing at least 200 people and devastating property in six states.

(Sigh.)

We’ve talked about disaster alerts before and how important they are. We’ve never talked about their timing, though. With sudden natural phenomena like tsunamis or tornadoes, alerts need to reach people immediately or they may as well not go out.

For as long as they’ve been around, radio and TV have been the primary emergency alert media other than sirens in urban areas.

Problem is, we’re not always listening to the radio or watching TV. Less and less every day, actually, at least as far as radio goes. Lots and lots of people don’t listen to the radio at all anymore, not when they’ve got thousands of songs on an iPod somewhere.

But everybody has a cell phone (or at least most people do), and they almost always have their phones on them. You hear people all the time saying how naked they feel without their phones. Out of touch. Isolated. Unreachable.

Which is exactly right, if we’re talking about sudden emergency alerts. If you have your cell phone on you, though, you’re on the grid, in touch, reachable.

I wonder how many people walked out of their home last night without hearing the radio or seeing the TV and had no idea tornadoes were tearing across their community.

Some communities have IVR systems set up to alert emergency personnel of impending disasters like last night. But what about the rest of us? There’s no reason every community in the country couldn’t have something set up.

You walk out the door. Your phone rings. A message gives you a tornado alert. You walk back inside, turn on the TV and get the whole story. You go to your basement. You wait it out.