The cyclone gathered pace as it bore down on the tiny island kingdom, which declared a state of emergency, warning residents to seek shelter from destructive winds and massive sea surges.
By early Thursday it had again become a scale-topping Category Five superstorm – surprising meteorologists after signs earlier in the week that its intensity was dropping.
Packing winds of up to 260 kilometres per hour (160 miles per hour), it cut power in parts of the country and police said at least three tourist resorts north of the capital Nuku’alofa had been reduced to rubble.
The cyclone killed 27 people in the Solomons late last week before barrelling southeast to directly hit Vanuatu as a Category Five, obliterating entire towns in the northern provinces.
There have been no reports of deaths in Vanuatu, Fiji or Tonga, with emergency workers saying residents in the hardest hit areas took shelter early.
“It appears that many buildings and crops have been destroyed and some people in the most affected areas have lost everything,” Red Cross Vanuatu secretary general Jacqueline de Gaillande said.
Harold weakened slightly to a still-formidable Category Four as it lashed Fiji on Wednesday but hopes the storm was dissipating were dashed when it regathered momentum heading towards Tonga.
“It’s been a tricky one to predict,” meteorologist Bill Singh from New Zealand’s Metservice told AFP.
“We knew the track it was going to take but initially everyone thought it was just going to be Cat 3 or 4, but as it progressed over open warm waters it deepened.” – AFP