From what I hear, they got a 20 minute warning, thanks to spotters and Doppler. I am the first to make jokes about metoroligists when i shovel 8 inches of "flurries" or get rained on when they said it would be clear and sunny. All joking aside we out here in Tornado Alley owe them and the chaser, the spotters and others like them a debt of graditude for what they have been able to do. When I was a kid, if the sirens sounded, it was already one the ground and most likely killing someone, the modern 20-30 minutes that they give folks most times has saved countless lives. My hat is off to these folks.