Devastating hurricane winds topping 160 miles-per-hour are likely to strike Bermuda at least once every 1,000 years.

According to predictive models, the Island could feel the force of a mega-power hurricane around once every millennium.

Hurricane expert Dr. Kerry Emanuel was on the Island to reveal the latest discoveries in hurricane research and also the history of the storms.

His itinerary included a public lecture, workshops on weather risk prediction and discussing with Island-based insurers what the latest thinking is on the subject.

Dr. Emanuel was booked as a guest speaker by the Bermuda Biological Station for Research (BBSR) before the storm devastation of Hurricanes Katrina and Rita along the US gulf coast added additional topicality to the subject.

The storms were at the forefront of his mind when The Royal Gazette met with the visiting professor from the Massachusetts Institute of Technology Program in Atmosphere, Oceans and Climate.

So why had the US suffered a hurricane double-whammy in a matter of weeks? Was it proof of global warming?

“It is all down to chance,” Dr. Emanuel said. “We were seeing the laws of chance operating there. Katrina was near maximum intensity when it hit landfall and it hit a very vulnerable place.

“Everyone was waiting for the shoe to drop on New Orleans and they knew it was coming one day.”

Those who watched Katrina develop in the Gulf knew it was going to be a giant storm, he said.

“The sea temperature of the gulf was warmer than usual, it was about 86F almost everywhere, but the biggest factor was that Katrina peaked as a storm while it was on the ‘loop current’,” he explained.

The loop current is a massive, swirling, warm sea current that snakes through the gulf and eventually becomes the Gulf Stream. But, unlike the Gulf Stream, which has warm water to a depth of around 20 metres, the loop current has warm water sinking to a depth of 100 metres.

“A hurricane churns up the sea water to a depth of 50 or 60 metres, so outside of the gulf it is putting cold water into the mix and so it is a self-limiting mechanism,’ Dr. Emanuel said. “But Katrina moved right up the axis of the loop current, we could see this from satellite data.”

As a result the only water being churned up at the extra depth was warm water. There was no cold water to slow down the developing storm.

“Those of us watching this felt an intense dread because the hurricane was by then a recipe for disaster,” Dr. Emanuel said.

The hurricane forecasters got their warnings spot on and even three days before Katrina struck land they had pinpointed its most likely impact point.

With Hurricane Rita a few weeks later, the same loop current gave it added power but it moved off the deep, warm water current a little longer than Katrina before reaching land and as a consequence had less destructive power.

The ability to predict storms and their likely trajectory is improving. What is still elusive is being able to predict what kind of wind strength and rainfall a hurricane is packing before it hits.

For Bermuda there is always a danger of a hurricane bearing down on the Island.

Dr. Emanuel said: “The hurricane tracks are to the west of Bermuda but winds can take them anywhere.

“My feeling is that the Island is better adapted to dealing with hurricanes because its people have become used to them and are more aware of their impact. And there are places of substantial elevation.”

As part of risk assessment, a computer programme has been devised to “fast forward” time and look at the likelihood of hurricanes of various strengths following historical tracks across the globe. The programme is based on the global climate remaining stable and can be used to show insurers and others with a vested interest the likely chance of a hurricane striking a given location in the future.

Some 3,000 storms were run through the programme across Bermuda’s path. A maximum strength hurricane with winds of 160 mph would only likely make a direct hit on Bermuda once every 1,000 years, according to Dr. Emanuel. A lesser storm, but still punching out destructive winds of 140 mph, would be expected to visit Bermuda every 100 years.

Such information is valuable to insurers when they reckon up the chances of the Island taking a big hit and the likely pay-outs that they would incur.

There is still much to learn about the science and nature of hurricanes, but one of the positives of the renewed interest in the storms of late will be, Dr. Emanuel believes, youngsters today growing up and pursuing a career in hurricane research.