Cumulonimbus
Cumulonimbus, from the Latin cumulus ("heap") and nimbus ("rainstorm", "storm cloud"), is a dense towering vertical cloud associated with thunderstorms and atmospheric instability, forming from water vapor carried by powerful upward air currents.
(Source: Wikipedia)
Mark squinted through the rain, his fingers tapping the steering wheel in a rapid beat, willing the red light to turn green,
Now! Now! Now!
He briefly entertained the thought of how it would be if he could change