BBC ; It has caused more than $10bn (£7.6bn) in damage across the Caribbean so far, disaster risk experts said on Friday.
That would make it the costliest storm ever to hit the region, the Centre for Disaster Management and Risk Reduction Technology said.
Airports are closed or inoperable and cruise lines have cancelled voyages.
Some parts of the region, such as St Kitts and Puerto Rico, faced extreme weather, but appear to have avoided the worst of the storm.
But other places have been shaken “to their core”, the secretary general of the Caribbean Tourism Organisation, Hugh Riley, told the BBC.
Mr Riley said people were currently focused on protecting lives.
“That’s first and foremost … but yes, clearly it has not escaped our attention that the economic wellbeing of the Caribbean is taking a hit,” he said. Irma is the second major storm to strike this season.
Financial analysts have estimated losses from Storm Harvey, which hit Texas and the Gulf of Mexico, at $90bn (£68bn), including damages and lost output. Texas officials say it could cost double that to rebuild.
Irma has caused an estimated $150m in damage on Barbuda, the island’s prime minister has estimated.
Damages on French islands are expected to exceed 200m euros (£180m), insurer Caisse Centrale de Reassurance said.
Irma has affected an estimated 1.2m people in the Caribbean before heading on to Florida in the US.
The $10bn estimate for the Caribbean does not include damage in the Dominican Republic or Cuba, which were later in the storm’s path.
Although many places are still assessing the damage from Irma, it is already clear that the combination of storms means 2017 is shaping up to be one of the costliest years ever for the insurance industry, Paul Schultz, chief executive of Aon Securities, told the BBC.
“Both from an economic perspective and from an insured perspective losses are going to be truly catastrophic,” he said.
Much of the damage sustained in Harvey was not covered by insurance.
Harvey’s path through the Gulf of Mexico and Texas disrupted oil production and refining plants and contributed to a spike in gas prices.
Those problems deepened in Florida this week, as families stocked up on petrol in advance of Irma. Price search site, GasBuddy, estimated that more than 40% of stations in some areas were without fuel as officials ordered evacuations.
Authorities in Florida said they had received thousands of reports of price gouging – whereby sellers raise prices beyond what is considered fair – on items such as petrol and water.
Several airlines pledged to cap prices on flights for evacuations, after an outcry over fare increases.
Those companies were already grappling with millions in losses stemming from cancelled flights related to Harvey.
Analysts said the airlines could face prolonged challenges, depending on the scale of the damage wrought by Irma in the tourist destinations of the Caribbean and Florida.
“Curtailed travel to the south and to the Caribbean is likely material,” analysts for The Buckingham Research Group wrote in a note.
An analysis of tourist traffic in the Caribbean found that it fell by 2% after a typical hurricane and by as much as 20% for major events.
At least two hotels on St Thomas in the US Virgin Islands have already said they will be closed for months. And another hurricane is on its way.
The US, UK, France and the Netherlands are among those providing help to places affected by the storm, but a long-term decline in travel would be a blow to a major driver of the Caribbean economy.
Tourism directly and indirectly contributed about 15% of Caribbean GDP last year, according to the World Trade Organization.
“There isn’t any question that we as Caribbean people know how to get up and stand on our feet,” said Mr Riley. “The question is how long it will take.”