Where Are Mammatus Clouds Common?

Where Are Mammatus Clouds Common? Most typically observed on cumulonimbus anvils, mammatus also occur on the underside of cirrus, cirrocumulus, altocumulus, altostratus, and stratocumulus, also as in contrails from jet aircraft and pyrocumulus ash clouds from volcanic eruptions. What does it mean when you see mammatus clouds? Mammatus clouds most often signal that a storm