Sir Richard Branson, the billionaire founder of the Virgin Group who said he would ride out Hurricane Irma from his 74-acre private island in the Caribbean, has emerged from his fortified wine cellar unscathed.

"All of the team who stayed on Necker and Moskito during the hurricane are safe and well," Branson said in a blog post, which he explained was transcribed with a satellite phone after the storm brought down all lines of communication.

"We took shelter from the strongest hurricane ever inside the concrete cellar on Necker and very, very fortunately it held firm. Our thoughts go out to everyone affected by the disaster elsewhere in the [British Virgin Islands], Caribbean and beyond," he said.

Apocalyptic scenes of flattened buildings and ruined airports emerged from once-lush Caribbean islands devastated by Hurricane Irma, as the deadly storm began to lash vulnerable Haiti and another powerful storm, Hurricane Jose, followed fast in its wake.

About 95 per cent of the tiny island of Barbuda, southeast from Necker Island, sustained damage, according to Gaston Browne, prime minister of Antigua and Barbuda. Ghastly photos and videos from St. Martin and St. Barthelemy, also known as St. Barts, showed buildings in ruin and cars and trucks almost submerged in the storm surge.

Branson had said earlier his compound was built with reinforced hurricane blinds designed to withstand high winds. But that wasn't the case for the surrounding area or the rest of Necker Island, his property for over 40 years.

"I have never seen anything like this hurricane. Necker and the whole area have been completely and utterly devastated. We are still assessing the damage, but whole houses and trees have disappeared," he said.

"Outside of the bunker, bathroom and bedroom doors and windows have flown 40 feet away."

True to form, Branson used his platform to call for donations and support.

"Virgin Unite has made a donation to the British Red Cross to support the hurricane relief efforts, and we are awaiting more information about how else we can best support. I would urge everyone to donate to the British Red Cross through Virgin Money Giving (who are waiving their fees in support of the appeal) to help local communities," he said, with a message readers in the British Virgin Islands to check in on Facebook to alert family members about their safety.

Branson is the 324th wealthiest person in the world, with a net worth of about $5 billion, according to Forbes, which notes that he bought Necker Island for $180,000.

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On Wednesday night, before Irma hit, Branson said he and his team experienced "howling wind and rain."

He posted pictures of people smiling and bedded down in a room filled with furniture, backpacks and makeshift beds.

"All of us slept together in two rooms," Branson wrote. "I haven't had a sleepover quite like it since I was a kid. Strangely, it's a privilege to experience what is turning into possibly the strongest storm ever with such a great group of young people.

"We were listening to the parrots in their boxes in the next room chattering away. Watching the tortoises congregating together, as if they sense what is coming our way."

A few hours before Irma's impact, Branson wrote that he planned to retreat with his team to his concrete wine cellar below "the Great House."

As one does.

"Knowing our wonderful team as I do, I suspect there will be little wine left in the cellar when we all emerge," he wrote on his blog.

And then, for hours: Silence.

No tweets, no Instagrams, no updates on Branson's blog - nothing.

Barbuda, Hurricane Irma – in pictures Show all 7 1 /7 Barbuda, Hurricane Irma – in pictures Barbuda, Hurricane Irma – in pictures A roof-less house in Barbuda ABS TV Barbuda, Hurricane Irma – in pictures A mobile network tower snapped in two by the hurricane ABS TV Barbuda, Hurricane Irma – in pictures The hurricane left debris strewn across the island Barbuda, Hurricane Irma – in pictures Rubble in the aftermath of the hurricane ABS TV Barbuda, Hurricane Irma – in pictures The destruction in Barbuda, as seen from an ABS TV helicopter ABS TV Barbuda, Hurricane Irma – in pictures As well as destroying most houses, the hurricane also left plenty of flooding ABS TV Barbuda, Hurricane Irma – in pictures Barbudan residents survey the damage ABS TV

The news from other islands in Irma's path was grim, with reports of widespread devastation and destruction, with at least 10 deaths recorded.

Barbuda, where Irma first made landfall, was left "barely habitable," according to government officials there.

On Instagram, the billionaire's son, Sam, noted the catastrophic strength of the storm - and pleaded with others in its path: "Please don't take this hurricane lightly if it is heading your way."

The elder Branson echoed the sentiment Thursday evening for people without access to fortified wine cellars.

"For those who are still in the path of Hurricane Irma, and Hurricane Jose to come, I cannot emphasise enough how important it is to put safety first and prepare as strongly as possible," he wrote.

"Having seen first-hand the power of this storm, please ensure you stay inside, ideally in organised shelters or other solid concrete structures with water, supplies and emergency contact plans."