This tornado is being pushed over by a strong cross-wind. For the most part, tornadoes remain vertical unless pushed over by wind.

This is an image of a wall cloud. Had this wall cloud been rotating, it would then have been classified as a funnel cloud.

This is another image of a wall cloud. This wall cloud was rotating and did eventually become a tornado.

This is the aftermath of a very weak tornado that touched down in the northern suburbs of Pittsburgh.