All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Scholars classify the signs that you mentioned under the Major Signs of the Hour. Huthayfah ibn Aseed Al-Ghifaari narrated that the Prophet, sallallaahu ‘alayhi wa sallam, said that that the Hour will not occur until it is preceded by ten (10) signs. He, sallallaahu ‘alayhi wa sallam, included in that the sun rising from the West, the emergence of smoke, the anti-Christ, the descent of ‘Eesaa (Jesus) Y'ajooj and M'ajooj, three landslides: one in the East, another in the West, and a third in the Arabian peninsula; and the final sign that will occur is the fire that will emerge in Yemen and drive people to their Gathering place. [Muslim]
Also, there are many Hadeeths that clearly indicate that the Mahdi will emerge. Scholars consider this as a Major Sign of the Hour, for it coincides with emergence of the anti-Christ and the descent of Eesaa (Jesus) .
Allaah Knows best.