The senate bill still allows casualty loss deduction only restricts to federally declared disaster. I heard some tax cheaters made phony casualty loss deduction and IRS doesn’t have all the resources to verify it, so politicians want get more revenue from it.
The definition of federally declared disaster I can find from IRS is:
A federally declared disaster is a disaster that occurred in an area declared by the President to be eligible for federal assistance under the Robert T. Stafford Disaster Relief and Emergency Assistance Act. It includes a major disaster or emergency declaration under the Act. See Publication 547, Casualties, Disasters, and Thefts, for more information.
Trump did approve a federal disaster declaration for California in response to October CA wildfires:
Since the 2 houses are still working on combined bill, I would be really surprised if the CA fire victims are not allowed for casualty loss claim in their 2017 tax return.
