My fence was uprooted and I had to fix it for $650.00. What do I write in the FMV before event box on the Casualty and Theft Worksheet?

[IsabellaG]

For Casualty Losses, you're allowed to deduct the reduction in the Fair Market Value of your property. This can be difficult to figure out, particularly for something like a damaged fence, but the cost of repairs ($650) can be used as a reasonable measurement of the reduction in the FMV, especially since you only repaired your fence and didn't replace it with a brand-new fence. Your before the event FMV could be any reasonable estimate that is $650 more than the FMV after the event.

Keep in mind that you can only claim casualty tax losses if your loss amounts to more than 10% of your adjusted gross income. 

See this link for more information about Casualty Losses.