E. Tornado Look-Alikes:
Virga or rain shafts are often reported as tornadoes. In Figure 17, we see a developing rain shaft, which is fuzzy in appearance. An intense rain column, as in Figure 18, can be more difficult. Although it looks similar to the violent tornado on the cover of this guide, its edges are much less distinct.  Mammatus clouds, as seen in Figure 19, are often mistaken for tornadoes. While mammatus often accompany severe thunderstorms (see Figure 1), they are not severe in themselves and may also accompany non-severe thunderstorms. The feature most often mistaken for a tornado is a scud cloud. These are ragged, low cloud fragments which usually are not attached to the cloud base. When the scud is attached to the cloud base, as in Figure 20, it is very difficult to distinguish it from a wall cloud or tornado. In this example, and for all tornado look-alikes, the key is to. LOOK FOR ORGANIZED AND SUSTAINED ROTATION ABOUT A NEARLY VERTICAL AXIS.