A US nuclear power company has disclosed that one of the tornadoes that hit the US at the weekend, killing at least 45 people and causing widespread damage, forced the shutdown of two of its reactors.
http://www.guardian.co.uk/world/2011/apr/18/us-tornadoes-shutdown-nuclear-reactors
http://www.guardian.co.uk/world/2011/apr/18/us-tornadoes-shutdown-nuclear-reactors