Yes. A tornado can start on a hill just as easily as it would on a plain.
No. A plane cannot start a tornado.
The tornado keeps going without being affected.
No. Contrary to popular belief hills do not stop tornadoes. In some cases they may even be harmful: if a tornado is approaching from behind a hill, you might not see it coming.
The average tornado travels at 35 mph.
The "fire tornado" forms from the fire; it doesn't really matter how the fire starts. Also, a "fire tornado" is more properly called a fire whirl as it technically isn't a tornado.
Humans cannot start tornadoes.
The first known use of the word "tornado" was in 1556.
Through a valley
Yes, in fact a thunderstorm is the only thing that can produce a tornado.
A typical tornado lasts 1-5 minutes.
No. A tornado starts in the clouds and extends towards the ground. Until it reaches the ground it is not a tornado but a funnel cloud.
i tornado alley