When the bridge is occupied from one end to the other, when the fringed stars fly from the east, then people will die on this bridge.
(Yawm al-Khalas, Kamil Sulayman, p. 515; Kitab Al-Fitan Wa Al-Malahim, p. 162; al-Mahajjat al-Bayda, Volume 4, p. 343; Besharat al-Islam, p. 60)

Indeed, God will reform the order (duty) of Mahdi overnight. 
Ibn Aby Shayba, Volume 15, p. 197

“The Prophet ( Salla llāhu ʿAlayhi Wa-alehe Wa-sallam):

‘... Than, Medina and its inhabitants will be shaken three times and God will throw every unbeliever and hypocrite in the Medina out!' he decreed."

(Bukhari 1758, Muslim 2943, Al-Tirmidhi 2243, Abu Ya'la 2940, al-Baghawi 2022, Ahmad 13392)

Abu Hurairah (Radi Allahu Anhu) narrated: “The Messenger of God (saas):
However, it was Medina. Just as the bellows of a blacksmith removes the rust from the iron, Medina will remove the malicious people!' he decreed."

(Bukhara 1752, Muslim 1382/488, Malik 2/887, Ibn Hibban 3723, al-Baghawi 2016, Ahma 2/332)