Casualty

A casualty is the damage, destruction, or loss of property resulting from an identifiable event that is sudden, unexpected, or unusual.

Deductible losses. Deductible casualty losses can result from a number of different causes, including:

Nondeductible losses. A casualty loss is not deductible if the damage or destruction is caused by the following.

Progressive deterioration. Loss of property due to progressive deterioration is not deductible as a casualty loss. This is because the damage results from a steadily operating cause or a normal process, rather than from a sudden event. The following are examples of damage due to progressive deterioration.