As far as destruction floods are way out front over everything else. Floods kill way more people than any other natural disaster. Avalanches, earthquakes, Tsunamis and wildfires kill more people and do more damage.
I figure a Tsunami is as risky as a killer meteor for us.
List of natural disasters by death toll - Wikipedia, the free encyclopedia
Lots of ways mother nature can reduce the population. Tornadoes are certainly a threat, but they are just a minor problem with today's technology.