Scud clouds vs. Wall clouds: what’s the difference?

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HARRISONBURG, Va (WHSV) — Severe weather season is not far away. It’s important to be able to identify different types of severe weather clouds.

Scud clouds can be misleading. They can look scary and can look very similar to a tornado. Scud clouds are low lying clouds that are usually below storm clouds. The catch about scud clouds are that they are very wispy and loose. They may look like tornadoes in a sense, but these clouds do not even rotate.

In most common cases, scud clouds are on the leading edge of a thunderstorm. Thunderstorms lift warm moist air into colder areas where the air saturates. Sometimes the air is so moist that this happens just above the surface. This is how a scud cloud forms.

Wall clouds are a little more concerning. Wall clouds come from a cumulonimbus cloud. They abruptly lower and can drop tornadoes. Wall clouds form when warm air rises, condenses, and overpowers a downdraft of a thunderstorm.

Wall clouds typically form in the southwestern portion of a supercell. Supercells typically move in a northeastern direction. As wall clouds form, they tend to rotate, tighten, and can drop significant tornadoes.

In summary, scud clouds are loose and do not rotate. Wall clouds are tightly condensed and rotate. Those are the clouds that tornadoes commonly fall from.


This is a wall cloud. Notice the low and tight cloud that has dropped from the base of the storm cloud.
This is a scud cloud. Notice how this cloud is very loose. Tornadoes are more tightly compacted and rotate unlike scud clouds.