“””hurricanes are wreaking ever-more havoc”””
Yes, a hurricane in 2017 will probably wreak more havoc than a hurricane in 1950 did.
But, the increased havoc is the result of new, fancy, and expensive buildings that have been constructed along the East Coast and Gulf Coast of the USA.
In 1950 many people built homes on the barrier islands of Florida. But those 1950 homes were cheaply built because the owner fully expected a hurricane would eventually blow the building down or flood.
Yes, the proper way to compare costs is either using damage as a percent of GDP, or normalizing the damage for the increased insured value of property. Real estate inflation in cities like Miami have far exceeded GDP or other price inflation.