Wall Cloud

A wall cloud (or pedestal cloud) is a large, lowering cloud formation that develops beneath the base of a cumulonimbus cloud that often forms tornadoes. It is typically beneath the rain-free base (RFB) portion of a thunderstorm, and indicates the area of the strongest updraft within a storm. Wall clouds are sometimes an indication of a rotating mesocyclone in a thunderstorm, and most strong tornadoes form from wall clouds. However, wall clouds do not always rotate.

Read more about Wall Cloud:  Genesis, Structure, Supercell and Tornado Significance

Famous quotes containing the words wall and/or cloud:

    What a troublesome thing a wall is! I thought it was to defend me, and not I it! Of course, if they had no wall, they would not need to have any sentinels.
    Henry David Thoreau (1817–1862)

    Hast ‘ou fashioned so airy a mood
    To draw up leaf from the root?
    Hast ‘ou found a cloud so light
    As seemed neither mist nor shade?
    Ezra Pound (1885–1972)