Armistice Day Blizzard

Although this isn't a recent hazard I find it a perfect example of the complexity paradigm. On November 11, 1940 the early afternoon temperature was 60 degrees f over much of the midwest. In a short period of time the temp. dropped 50 degrees and record low pressures were recorded in La Crosse, WI. The result was an intense blizzard with snow accumulation up to 27in and drifts up to 20ft. 145 people were killed by the storm, most of them being duck hunters along the Mississippi. Those who survived described 1000's of ducks flying across the river most of them being blown through the air by the wind. This event is often ranked among the top weather events in the 20th century.

http://en.wikipedia.org/wiki/Armistice_Day_Blizzard