I found the following couple of hadiths from the Sahih Bukhari:
Volume 9, Book 87, Number 162:
Narrated 'Abdullah bin 'Umar:
concerning the dream of the Prophet in Medina: The Prophet said,
"I saw (in a dream) a black woman with unkempt hair going out of Medina and settling at Mahai'a. I
interpreted that as (a symbol of) the
epidemic of Medina being transferred to Mahai'a, namely, Al-Juhfa."
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Volume 9, Book 87, Number 163:
Narrated Salim's father:
The Prophet said, "I
saw (in a dream) a black woman with unkempt hair going out of Medina and settling in Mahai'a. I interpreted that
as (a symbol of) epidemic of Medina being transferred to Mahai'a, namely, Al-Juhfa."
Why a black woman?
What does a dream of a black woman have to do with the spread of an epidemic?