 While he was Bishop of Mauritius, the island experienced one of its worst cyclones; in consequence his cathedral had to be used temporarily as a hospital.Walsh's great-great-grandfather was Reverend Philip Walsh (1655–1740) who was the Prebendary of Tipperkevin, Vicar of Blessington, Rector of Ballymore Eustace, and chaplain to Primate Michael Boyle, Archbishop of Armagh.His mother was Augusta Junietta Thwaites (1797-1873) and his father was Irish born Lieutenant William Walsh (1798-1839) of the 7th Royal Fusiliers.