For casualty losses, you can deduct your loss without regard to the usual limits on such deductions, meaning you can deduct the loss even if you don't itemize your other personal deductions.
https://www.irs.gov/taxtopics/tc515
Your loss is the loss in value of the property caused by the storm. If you repair/restore the property to as-was condition, then your costs are allowed to be taken as a a fair estimate of the loss. But if you did not restore the property, or if you made the property better (such as using the insurance money to remodel an outdated kitchen) then you may need an appraisal to determine the amount of your loss. You also can't deduct any part of your loss that was covered by insurance, or that would have been covered by insurance except you decided not to file a claim.
You claim the loss deduction (if you have one) on your tax return using form 4684. You must include the FEMA number of the disaster on your tax return, that will tell the IRS that you are claiming a qualified disaster loss.
Other provisions (like penalty waivers) are explained on the IRS web site at the link provided.
