According to the IRS, "A federal casualty loss is an individual's casualty or theft loss of personal-use property that is attributable to a federally declared disaster. The casualty loss must occur in a state receiving a federal disaster declaration."
Beginning in tax year 2018, losses from events other than federally declared disaster areas are no longer allowed.
For tax years prior to 2018, you may still claim a casualty or loss due to fire, flood, etc not connected to a federally declared disaster on your tax return.