To claim casualty loss from LA fires, can replacement cost reported by my insurance be used as a proxy for FMV? Also, although in 2025 it can be claimed on 2024, correct?

[wkassin]

Also, is deduction subject to 10% floor for this disaster?

[MarilynG1]

Yes, you can use the replacement cost as your FMV before the disaster. 

If you or your business is in a federally declared disaster area and you suffered uninsured or unreimbursed disaster-related losses, you can choose to claim them on your 2024 taxes being filed in 2025 instead of waiting to claim them on your 2025 taxes which will be filed in 2026. Be sure to write the FEMA declaration number – 4856-DR − on any return claiming a loss. 

Here's more detailed info on California Wildfire IRS Tax Relief.

@wkassin