Tropical Cyclone Evan has moved past the Samoan capital of Apia, but is due to reverse back over the Pacific island nation later tonight, delivering a double dose of destruction.
With night fallen on the city, residents have not had a chance to fully assess damage, but several arterial routes have been blocked and landmarks damaged.
There are still unconfirmed reports of deaths.
Residents were being urged to move to higher ground as they braced for another pounding in the early morning, this time possibly stronger with winds of up to 190km/h, before it heads towards Fiji.
Samoa's National Disaster Management Office says the damage from the cyclone has been officially declared a disaster, and it has now issued warnings to residents in the areas of Vasigano, Lelata, Almagoto, Moamoa and Tufuiopa to vacate the lowlands and seek safety in the hills.
The Apaula Heights Lounge on Mt Vaea has been opened as a refuge centre for fleeing residents.
Reports from Apia suggest electricity supplies and the internet have been affected, and with phone batteries running low contact with the outside world is now reduced.
Among the landmarks reported damaged by witnesses is the famous Aggie Grey's Hotel, just out of Apia. The Leone Bridge has washed away and two others in the city are under water.
The National Environmental Satellite Data and Information Service has posted this satellite image of the storm's progress across Samoa.
Cyclone Evan is likely to intensify and is threatening the vulnerable Tongan islands of Niuafo'ou and Niuatoputapu, which were devastated by the 2009 tsunami which killed 189 people in the region.
Tourists staying in beach fales around the country have been told to move inland, and schools and government offices have closed.
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Cyclone Evan was named yesterday by the regional Tropical Cyclone Centre in Nadi, Fiji, after a tropical depression worsened southwest of Samoa, before moving east towards Apia.
The storm is expected to ease a serious water shortage in Samoa, where rains have been light and water catchments are dry.
The acting managing director of the Samoa Water Authority, Ekiumeni Fauolo, told Radio Australia that he has never seen weather patterns like these in Samoa.
"This is supposed to be our rainy season," he said. "It should have started two months ago, three months ago, but we haven't seen any decent rain."