White, shaggy cloudlets...
"The day grew hot. White, shaggy cloudlets were flitting rapidly from the snow-clad mountains, giving promise of a thunderstorm; the summit of Mount Mashuk was smoking like a just extinguished torch; grey wisps of cloud were coiling and creeping like snakes around it, arrested in their rapid sweep and, as it were, hooked to its prickly brushwood. The atmosphere was charged with electricity."
From 'A Hero of Our Time'