The three conditions needed are warm earth, moist air, and a trigger. As the drop of water travels upward, it collides with other super-cooled drops, all the while growing bigger. Both lightning and static electricity involve electrons that travel from a negative to a positive area, liberating energy. Slow moving thunderstorms drop an unusual amount of rain on a small area that cannot be absorbed into the ground. Two or more gully-washing thunderstorms hit the same spot, one after another.
Heavy rain falls on rapidly melting snow.
The difference between tornadoes and hurricanes is that tornadoes are small, while hurricanes cover hundreds of miles. A tornado watch means conditions are right for a tornado to form. A tornado warning means one has been spotted or detected from Doppler radar. Answers in Genesis Ministries International. A member of the Gospel Communications Network .