Khasf al-Bayda

Khasf al-Bayda (Arabic: خسف البیداء) ( lit. “Swallowing the land of Bayda” ),   in Islamic eschatology, is a future event in which the Earth will swallow up Bayda, a desert area between Mecca and Medina. According to Islamic traditions: the army of Sufyani will be swallowed up in the land of Bayda.

Khasf al-Bayda has been mentioned in both Shia and Sunni sources, and it was narrated that "Khasf al-Bayda" will be is going to be one of the decisive signs of the appearance of Mahdi.

The certain signs
According to hadiths, there are five (or more) certain signs which will happen prior to the reappearance of the twelfth (last) Imam of Shia Islam, al-Mahdi. Al-Shaykh al-Saduq has narrated --from Ja'far al-Sadiq-- that: five signs are decisive before the rising of Qa'im (قائم): Yamani, Sufyani, Heavenly cry (calling) from the sky, The murder of Nafs-e-Zakiyyah and Khasf al-Bayda.

Swallowing of the army
Sufyani and his army will go toward Iraq to attack the Mahdi. When the army enters the territory of Bayda, the Earth will consume the army of Sufyani except for 2 or 3 individuals. Various hadiths discuss the numbers in the army of Sufyani. Some sources say that the army of Sufyani will number 12,000; while some say 170,000  and other sources say 300,000

According to a tradition from Muhammad al-Baqir: at the End Time, when Sufyani's army enters the territory of Bayda, a voice will call out: ""O plain, annihilate the nation" (i.e. the army of Sufyani)"