UPDATE: Tornados deliver perfect storm for high death toll, now at 280

PLEASANT GROVE, Ala. (AP)

Firefighters searched one splintered pile after another for survivors Thursday, combing the remains of houses and neighborhoods pulverized by the nation's deadliest tornado outbreak in almost four decades.

At least 280 people were killed across six states - more than two-thirds of them in Alabama, where large cities bore the half-mile-wide scars the twisters left behind.

The death toll from Wednesday's storms seems out of a bygone era, before Doppler radar and pinpoint satellite forecasts were around to warn communities of severe weather.

Residents were told the tornadoes were coming up to 24 minutes ahead of time, but they were just too wide, too powerful and too locked onto populated areas to avoid a horrifying body count.