He—may Allah have mercy on him—was asked:

A man leased land without knowing its area, to use for resting at midday and at night, grazing, and cultivation over a period of seven years. The land flooded and became submerged, leaving him unable to benefit from it. When it flooded, he sought cancellation of the lease by mutual agreement. The lease still had time to run when the flooding occurred, and the remaining benefit was lost. Must he pay rent for the year in which it flooded and became submerged? And may his request for cancellation be granted?

He replied:

Leasing a specified parcel of land is permissible even if its area is unknown, just as selling it or any other specified property is permissible even if its quantity is unknown. Selling a specified property as a whole, without measuring it, is permissible according to the Sunnah and scholarly consensus. It is established that the Prophet, may Allah bless him and grant him peace, permitted the sale of a jointly owned share in land, a dwelling, or an orchard, and the sale of fruit on the trees once its soundness had become apparent. He also approved their practice of selling food in bulk without measuring it.

If the land can no longer be used because of flooding or any other cause, no rent is due for the use that has been lost, by agreement of the Muslims.