Total economic losses from Tropical Storm Harvey could be as high as $70 billion to $90 billion — but the vast majority of the losses will be uninsured.

That is the latest finding of catastrophe modelling firm RMS, which says Harvey is a rainfall record-breaker and that the bulk of the losses will come from flooding in the Houston metropolitan area.

Some of Bermuda’s reinsurers are likely to make substantial payouts, as the insurers that they cover will be hit by a slew of property and business interruption claims in the coming weeks.

Given that most of the damage will come flooding and private flood insurance is limited, RMS said in a preliminary estimate that most of the losses would be uninsured.

“However, although the insured losses will remain uncertain for some time they will be significant, as private coverage is not consistent: there are significant variations in how coverage is provided by individual insurers,” RMS said.

Michael Young, RMS head of Americas climate risk modelling, said: “Hurricane Harvey has already broken all US records for tropical cyclone-driven extreme rainfall, with observed cumulative amounts of 51 inches.

“And with the rain still falling heavily and the waters rising, the situation is too fast-moving to be stating with certainty what the losses in Texas could be.”

RMS added that the estimated losses represented “preliminary insights” and were the result of analysis produced by its US High Definition Flood Model. The modeller will issue an official insurance loss estimate for the storm “in the coming weeks”, Mr Young added.

Warren Buffett, chairman and CEO of Berkshire Hathaway, expects a significant impact for insurer Geico, a Berkshire company. Around 50,000 of the 500,000 cars Geico insures in the affected area would probably be total losses, he said.

RMS said last week that wind damage from Harvey would likely lead to insurance losses below $6 billion.

Modelling firm Air Worldwide said earlier this week the insured losses from Harvey’s wind and storm surge were estimated at between $1.2 billon and $2.3 billion. That figure does not include flooding.

Analytics firm Corelogic yesterday raised its estimate for wind and storm surge insured property losses, excluding flooding, to $1.5 billion to $3 billion from $1 billion to $2 billion.