As I posted on the main page of my website, extensive damage across the Kansas City area was experienced during the early morning hours of May 2, 2008.
There were a couple of rounds of severe weather to hit the area, but by far the biggest impact was during the second event. A squall line formed in association with a cold front, and went on to create what is known as a Bow Echo on radar. Often these bow echos are associated with much higher winds, and widespread straight-line wind damage. Due to the intensity of this one, a couple of tornadoes also formed up, one near Liberty, MO, which caused the above damage and was rated at EF3 on the Enhanced Fujita Scale.
Winds in excess of 80 mph were generated within this line. According the the NWS, this line engulfed some other storms ahead of the line and also generated tornadoes in the area.
You can see more of their ongoing assessment, as well as more damage pictures on their website.