Question

Which type of cloud often indicates that a storm is on the way

Answer 1

I googled and found this:
"Cumulonimbus are generally known as thunderstorm clouds. High winds will flatten the top of the cloud into an anvil-like shape. Cumulonimbus are associated with heavy rain, snow, hail, lightning, and tornadoes. The anvil usually points in the direction the storm is moving."
You could have googled it too and gotten your answer much faster.