Yep! Today is the joint feast of the Dedication of St. Mary Major in Rome and of Our Lady of Snows.
The link above describes:
The first church here was founded in the 350's by Pope Liberius, and financed by a Roman patrician and his wife. They were childless, and had decided to leave their fortune to the Blessed Virgin. She appeared to them in a dream and told them to build a church in her honour. It lies on the summit of the Esquiline Hill, which was mainly laid out as gardens in ancient times. Legend claims that the plan of the church was outlined by a miraculous snowfall in August (possibly in 358). The legend is commemorated every year on 5 August, when white rose petals are dropped from the dome during the Mass.
Pope Sixtus III had it restored, or more likely rebuilt, to commemorate the declaration of St Mary's Divine Motherhood by the Council of Ephesus in 432.
The church was damaged in the earthquake of 1348, and restored some years later.
See video of the 'snow fall' from today's Mass:
By the by, this was the Church in which Mom stood agape by it's size and beauty. When informed 'this is the small one,' she looked at me askance. Well, at least until we entered St. Peter's. Then she knew I wasn't pulling her leg!