Catastrophe modelling firm AIR Worldwide estimates that insured losses in Bermuda from Hurricane Gonzalo will range between $200 million and $400 million.

AIR conducted a damage survey across Bermuda on Sunday and Monday. In a statement, AIR said: “In the areas surveyed, damage was mostly limited to roofs but structural damage was seen on older buildings, including some historical ones.

“Most resorts on the Island withstood the storm very well, sustaining only minor roof damage to one or two units that were more directly exposed to high winds.

“Some roof damage caused by Tropical Storm Fay a week earlier was still under repair when Hurricane Gonzalo struck. Roof damage ranged from superficial, with just a few tiles removed, to severe — although in most cases, the interiors were not breached.

“Less common, but still seen in several areas, was heavier damage to older buildings or to buildings that were less well maintained or not subject to strict building codes (such as warehouses or garages).”

AIR said Gonzalo’s eye was “very large” with a diameter of 30 miles, leading to about 90 minutes of eerie calm as it passed directly over the Island.

Scott Stransky, manager and principal scientist at AIR Worldwide, said: “When the eye began to come onshore, the storm was still a Category 3 hurricane with 115mph sustained winds. However, by the time the centre passed overhead, Gonzalo had weakened to a Category 2 hurricane, with 110mph sustained winds.

“The strongest observed winds at Bermuda International Airport were 93mph sustained, with gusts of 113mph. The storm weakened prior to landfall due to both lower sea surface temperatures and higher wind shear in the vicinity of Bermuda.

“Note that the centre of Tropical Storm Fay passed directly over the Island less than a week ago. It is likely that Fay’s passage reduced the sea surface temperatures around Bermuda, allowing Gonzalo to be just slightly weaker than it might have been otherwise.”

AIR said most of the newer and well-maintained buildings that meet Bermuda’s building codes stood up well to Gonzalo’s winds, with only minor damage to roof areas that were directly exposed to the oncoming storm.

“Gonzalo’s track may have also mitigated the damage in Bermuda,” AIR added. “Building damage from winds is due to both wind speed and duration. Thus, the damage caused by Gonzalo was not as bad as it potentially could have been because Gonzalo’s eye (the calm of the storm) enveloped the entire territory as it passed directly overhead, thereby reducing the amount of time buildings were exposed to heavy winds.”

AIR’s estimation includes damage to onshore property and business interruption, but does not include damage to boats.

The estimated damage tally compares to Fabian-related losses of $300 million (in 2003 dollars); AIR estimates that a recurrence of Fabian today — with today’s exposures — would result in insured losses of around $650 million.