Hidden between several layers of clouds, a gigantic thunderstorm has grown far above our cruising altitudes.
Fortunately we have strong weather radar on board that can look ahead through the thick moist of clouds where our human eyes cannot reach, but once we broke clear of the grey mist and saw this enormous boiling mountain of violent hail and winds, I was impressed nonetheless.
Stationary for the inattentive observer, the cloud is actually growing rapidly and should be dealt with carefully since its forces can easily damage an airplane that ventures inside.