A tornado affects anyone unfortunate enough to be in the path of one.
No, lightning has little to no affect on a tornado.
The area of greatest tornado activity appears to be shifting northward. It is unknown how this might affect tornado intensity.
Yes. A river, forked or not, will not affect a tornado.
Nothing happens. The lightning will not affect the tornado.
Yes, a tornado is not considered a tornado unless it reaches the ground.
The main impact of a tornado on ecosystems is the destruction of trees and other vegetation. Animals caught in a tornado may be killed or injured as well.
The primary force at work in a tornado is a pressure gradient force. Pressure inside a tornado is lower than it is outside, which causes the path of any air near it to curve toward the center of the tornado. Slight variations in that pressure can affect how a tornado behaves, which is part of what makes tornadoes so hard to predict.
Most likely about 700 tornadoes affect tornado alley each year.
Possibly. There is some evidence that the most frequent tornado activity in Tornado Alley has shifted northward.
Oklahoma is in Tornado Alley. Tornadoes rarely affect Nevada.
Tornadoes do not affect climate. Climate is the long term trend in weather patterns while a tornado is a short lived effect. Temperature inside a tornado is lower than it is in the surrounding environment. However, you would only experience this while inside the tornado itself.
People and animals may be killed or injured in a tornado and lose their homes. Buildings may be damaged or destroyed.