Salma said:
I went in to visit Umm Salama and found her weeping. I asked her what was making her weep and she replied that she had seen God's messenger (meaning in a dream) with dust on his head and beard. She asked him what was the matter and he replied, "I have just been present at the slaying of al-Husain."
Tirmidhi transmitted it, saying this is a gharib tradition.