سنن النسائي

It was narrated that Abu Hurairah said: "The Messenger of Allah (ﷺ) would say: [1] 'Allahummaghsil khatayaya bi-ma'ith-thalj wal-barad (O Allah, wash away my sins with the water of snow and hail).'" [1] That is at the beginning of Salah as is clear from the remainder of the narration which preceded under No. 60.