From similarity and differences of morphological, biochemical, cellular characteristics, biologist have constructed 'phylogenetic (evolutionary) trees' (who is most closely related to who, analogous to a family tree)
In the United States, lightning routinely kills more people each year than tornadoes or hurricanes. Tornadoes, hail, and wind gusts get the most attention, but only lightning can strike outside the storm itself. Lightning is the first thunderstorm hazard to arrive and the last to leave.
Tornadoes are the most violent storms in nature. An average of 800 tornadoes are reported each year, resulting in 80 deaths and 1,500 injuries. Tornadoes are a worldwide phenomenon, touching down in every continent save Antarctica.