How Hammad bin Esa died?

From Umayyah bin Ali al Qaysi who said: I and Hammad bin Esa entered to see Abu Jafar (as) [i.e; Imam al Jawad (as)] at Medinah to bid Him farewell.
He (as) said to us: Do not go out, stay until the morning.
He (Umayyah bin Ali al Qaysi) said: When we went out from His presence, Hammad said: I will go out, for my luggage has gone out.
I replied: As for me, I shall be staying.
He (the narrator) said: Hammad went out and the valley flooded that night, and he drowned in it, and his grave is at Sayalah (السيالة).