Looking at some of these cloud types in closer detail:

Cumulonimbus
Cumulonimbus is a heaped rain bearing cloud that may spread from as far as 10 km across and 10 km above ground level, and will often resemble a huge cauliflower of sprouting towers. The higher levels of the cumulonimbus contain ice and are more fibrous in appearance. When the cloud is fully developed, this icy top section may flatten to form an ‘anvil’ shape. At this stage, the base of the cloud is dark with heavy short sharp showers of rain, hail or snow falling. These clouds have a lifespan of less than an hour, and can be seen at any time of day, more commonly though inland during the afternoon in the spring and summer.