Atmosphere Academy: How tornadoes form

We all know what they look like, and we know what they are capable of doing, but do you know how tornadoes form? There are 4 main ingredients you need for tornadoes to form: moisture, instability, lift, and wind shear. Moisture and instability are fairly obvious, but "lift" and "wind shear" are a little more mysterious. For complete details, click on the video link above to see an animation of tornado formation.