No. While strange colors have been reported before or during a tornado, such phenomena are not directly linked with tornadoes, nor are they necessary for tornadoes to occur.
There isn't an actual answer to this, because that's not how tornadoes work. The sky (not the clouds) does often turn a peculiar color when conditions are favorable for tornadoes to form, but it's...
Cumulus clouds can develop into cumulonimbus clouds, which are usually thunderstorms. All thunderstorms contain an updraft, which is a rising air current. Under the right conditions this updraft can...
Clouds themselves are not what forms a tornado, at least not directly. The process is complicated. First, a condition called wind shear, in which the speed or direction of the wind changes with...