Among all cloud types, the vertical cloud is the largest in three dimensions. When the cumulonimbus is weakening and dissipating, this cloud may appear from the low cloud group up to the high cloud group. For example, the cloud anvil belongs to the high cloud group. Usually the cumulonimbus clouds develop and diverge from the top of the troposphere and form pseudo-cirrus clouds. The anvil cloud is thick but still able to determine the position of the sun or moon behind cloud. At the middle layer of this cloud, it can produce nimbostratus, altocumulus and altocumulus. And lower level, it can produce stratocumulus, stratus or fragmented cumulus, etc. When cumulonimbus clouds mature, they are usually accompanied by severe rains, lightning, strong gusts, hail or tornadoes and other weather phenomena. If you look at cumulonimbus clouds from a distance, the clouds are like mushroom-shaped clouds. At the bottom part there will be a rolling cloud under the cloud, which is the gust front. The gust from is formed when the downdraft reaches to the ground and lift the worm air up at the leading edge for the gust then form roll cloud