An involuntary deposit is made: (1) by the accidental leaving or placing of personal property in the possession of any person, without negligence on the part of the owner; or (2) in cases of fire, shipwreck, inundation, insurrection, riot, or like extraordinary emergencies, by the owner of personal property committing it out of necessity to the care of any person.
Involuntary Deposit -- How Made
Mont. Code Ann. § 70-6-103, under Nature and Classification of Deposits.
Mont. Code Ann. § 70-6-103