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.
Even then, we still don't know why some thunderstorms create tornadoes while others don't, tornado-chaser Tim Samaras said in early 2013. Samaras was a scientist and National Geographic explorer who was killed by a twister on May 31, 2013, in El Reno, Oklahoma.