They are dark and heavy-looking, and rise like mountains high into the atmosphere.
They are dark and heavy-looking, and rise like mountains high into the atmosphere. They often show an anvil-shaped veil of ice clouds at the top. They can exist as individual towers or form a line of towers called a squall line, which is often present at cold fronts. For 10 points, name these clouds, which are popularly known as thunderheads and are usually accompanied by heavy, abrupt showers.
They are dark and heavy-looking, and rise like mountains high into the atmosphere.
{Cumulonimbus} clouds