A "scared" British family have been told they cannot leave their hotel on Skiathos after the Greek resort island was hit by torrential rain and flooding.
Becky Taylor, her mother Emma Taylor and her grandfather, who is aged in his late 70s, have been there for a couple of days on holiday.
But they said that over the past 24 hours there had been constant rainfall from Storm Daniel as well as thunderstorms and lightning, with power cuts.
Pictures from the island showed torrents of water gushing through streets and sweeping cars away.
The man died near the port city of Volos on the Greek mainland when a wall fell on him, according to the fire service.
Five people were reported missing, possibly swept away by floodwaters.
Ms Taylor told Sky News all the roads on Skiathos had been shut, with police advising everyone through alerts to stay in their hotels.
She said it was a "scary situation", with all the flights at the airport being cancelled - with 300 tourists reportedly stranded there.
Speaking from the Skiathos Palace Koukanaries hotel, Ms Taylor said: "We've had flooding, the hotel's full of buckets of water leaking from the ceilings… and the bottom floor rooms have experienced flooding."
She added: "The levels of water just keep getting higher."
"We can see down to the beach where numerous sunbeds are floating out to sea, they have been completely abandoned."
She also said she felt sorry for the local people whose homes and businesses had been "completely devastated".
Her mother Emma said the situation was "literally off the scale" and "it's just been biblical".
"We've been to many places in the world and we've never experienced a storm like this," she said.
"We have witnessed a hurricane in the Azores, we have witnessed storms before, this is out there with the most really dramatic, intense storm."
She continued: "It is quite a big disaster out here."
Greece's minister for civil protection, Vassilis Kikilias, said the storms were forecast to ease after noon on Wednesday and urged people in affected areas to stay indoors.
"According to meteorologists, it's the most extreme event as far as maximum rainfall in a day is concerned since record-keeping started," he said.
He added that in one part of nearby Pelion on the Greek mainland some 6.45cm (2.5in) of rain had fallen by early afternoon on Tuesday.
The storm comes after wildfires scorched Greece's Evros region near the border with Turkey for more than two weeks.
They were blamed for the deaths of 20 people - believed to be Turkish migrants.