SB 8.10.49
tato maha-ghana vyomni
gambhira-parusa-svanah
angaran mumucur vatair
ahatah stanayitnavah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Fierce clouds, harassed by strong winds, then appeared in the sky. Rumbling very gravely with the sound of thunder, they began to shower live coals.