How to prepare flood loss for tax return?

[Huiping S.]

Lots families were flooded from Hurricane Helene. The flood insurance will cover limited, structure may or may not the contents. Lots people's car, appliances were died. The loss is very big for those family. I drove through some community and like a after war field. 

How those people should be prepared to report loss on tax return? How detail to keep the loss?

Hope tax professionals or experienced people can give some suggestion.

Thanks!