“Lady in white" as they tell it, does not really correspond to any known entity/myth. It was what Raimunda referred to her as. She said the lady sat behind a window looking out into a snow covered landscape and said she saw horrible things in the snow and was trying to see if she could stop those things from happening. Raimunda was told (by the lady) that she had seen a tall man fitting Jose's description standing in fire surrounded by bodies
When we camped at the old falling in cabin, our previous visit to Mexico, to find Joan, John said he saw a woman sitting in a chair dressed in white behind a window. She said something to him, but I can’t remember what it was.