"The Prophet ﷺ used to say: 'Allahummaghsil khatayaya bi-ma'ith-thalj wal-barad was naqqi qalbi min al-khataya kama naqayta ath-thawb al-abyad min ad-danas (O Allah, wash away my sins with the water of snow and hail, and cleanse my heart of snow and hail, and cleanse my heart of sin as a white garment is cleansed of filth).'"  

كَانَ رَسُولُ اللَّهِ ﷺ يَقُولُ اللَّهُمَّ اغْسِلْ خَطَايَاىَ بِمَاءِ الثَّلْجِ وَالْبَرَدِ وَنَقِّ قَلْبِي مِنَ الْخَطَايَا كَمَا نَقَّيْتَ الثَّوْبَ الأَبْيَضَ مِنَ الدَّنَسِ  

"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.  

كَانَ رَسُولُ اللَّهِ ﷺ يَقُولُ اللَّهُمَّ اغْسِلْنِي مِنْ خَطَايَاىَ بِالثَّلْجِ وَالْمَاءِ وَالْبَرَدِ