Kashmiri Hindus had a tradition of carving Linga with snow on Shivaratri. Jabbar Khan, Afghan governor, banned Shivaratri & ordered Hindus to celebrate festival in snow-less Ashadha month(June-July).
That year, it miraculously snowed in Ashadha and Shivaratri was celebrated. Everybody was shocked (Hairat means shock in Persian) and festival was celebrated. Kashmiris have a saying "Wuchton yih Jabbar, jandah, Haras tih karun wandah" - "look at Jabbar wretch, he turned Hara into snow".
Incidentally, Jabbar was the last Afghan governor of Kashmir. Within 8 years of this incident, a general of Maharaja Ranjit Singh named Misr Diwan Chand (who himself was an ardent Shiva devotee) invaded Kashmir & Afghan rule came to an end. Afghans were expelled from Kashmir.
General Misr Diwan Chand deafeated the Afghans and expelled them from Kashmir