This is what happens when the hydaulics lock out and the blades can't be pitched out of the wind causing the turbine to over speed as the break can't handle the load. The wind had increased to 80 mph during a storm... this is a Vestas turbine over seas.
http://www.youtube.com/watch?v=QL-cRuYAxg0
http://www.youtube.com/watch?v=QL-cRuYAxg0