We had a localised SMS warning before Cyclone Yasi...
...and it confused everyone. A text that basically said "Cyclone Yasi is coming. Evacuate now. We're all doomed" is less than helpful. Which direction should people head, north or south? Even more ridiculous is that the cyclone was so big that no one could have driven out of the area unless they were on the margins.
They really need to think this one through a bit more.