The clouds looked like an armada of sailing ships gliding across the sky. It began peacefully with puffy white cumulus humilis clouds basking in the sunshine as plumes of air rose up from the warm ground, tiny cloud droplets coalescing on specks of dust, pollen grains, sea salt and even bacteria. Gradually the clouds grew into unmistakeable cumulus mediocris — dense white with clean-cut flat bases, typically some 600m above the ground with puffy rounded tops.
From the mediocris developed mighty cumulus congestus, an evocative name well suited to a cloud bursting with energy, as tall as it is wide, with turrets punching a mile or more into the sky. And the clouds billowed larger as the thermals of rising air continued lifting their payload
