The Collaborative International Dictionary of English v.0.48:

fire sale \fire sale\ n.
   1. a sale of objects damaged by fire, usually at much reduced
      prices.
      [PJC]

   2. A sale of objects or assets at much reduced prices, often
      performed to raise money rapidly.
      [PJC]

WordNet (r) 3.0 (2006):

fire sale
    n 1: a sale of assets at very low prices typically when the
         seller faces bankruptcy
    2: a sale of merchandise supposedly damaged by fire