Hurricane Irma could land insurers with a bill several times that of Storm Harvey if it hits Florida later this week as predicted.
Experts today raised the prospect of Irma making landfall in the US to as much as 80 per cent.
Florida has declared a state of emergency as the state prepares to be lashed by the 120mph winds currently recorded as Irma winds its way across the Atlantic.
And because it is winds rather than rain that will be the critical issue, insurance firms will pick up a larger proportion of the bill for costs instead of government-backed flood protection schemes.
AccuWeather meteorologist Tyler Roys said it was unlikely rainfall would be measured in "feet", as was the case with Harvey.
Damage to property was more likely to be a result of wind, Roys said.
Panmure Gordon head of research Barrie Cornes explained wind damage is covered by commercial insurance policies rather than state-backed schemes. This means as much as 70 per cent of economic losses are likely to be shouldered by insurance firms.
The figure compares with 20-25 per cent of Hurricane Harvey losses expected to be borne by insurers. A large proportion of costs will instead be covered by the US government's National Flood Insurance Programme (NFIP).
Many of the world's catastrophe policies are underwritten by Lloyd's of London insurers.
However, most members will only retain a fraction of the overall risk, instead choosing to offload it to large reinsurers.
Irma has already strengthened to a Category 4 storm. Experts say there is a chance it will strengthen to a Category 5 hurricane and are predicting it will make landfall in the US this weekend.
Roys also warned US government programmes could be severely stretched. It is 102 years since two Category 4 storms hit the US in the same year.