Musnad Abu Ya'la al-Mawsili 111:51

Muhammad al-Ahmasi narrated to us, Muhammad bin Fudayl narrated to us, al-Kalbi narrated to us, from Abu Salih, from Ibn Abbas regarding His saying: "And We sent down from the rain-clouds pouring water." He said: The *mu'sirat* (rain-clouds) are the winds. *Thajjajan* (pouring) means pouring forth.