The island of Chuuk, part of the Federated States of Micronesia (FSM), received a direct hit late on Sunday from Typhoon Maysak with the Yap group next in its path.
"Chuuk was devastated," lawyer Kembo Mida said in an email to the Ayuda Foundation relief organisation which is based in Guam about 1,000 kilometres (600 miles) away.
"Houses were blown away and trees snapped in half. It was very dangerous and scary... A ship sank too."
The director of the FSM National Emergency Management Office, Andrew Yatilman, told Radio New Zealand the typhoon scored a direct hit on the most populated area of Chuuk, which is home to nearly 50,000 people.
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"Residences (had) their roofs completely torn off, and so whoever was staying in those will have to be accommodated either by relatives or in public shelters that have been set up by the government," he said.
FSM Consul General Robert Ruecho told the Marianas Variety newspaper in Guam that he had not been able to make contact with people in Chuuk.
"I haven't been able to speak with the governor," Ruecho said. "The phone lines have been difficult today, power is down and so my information is second hand from the (FSM) capital in Pohnpei.
"Lots of flooding and many of the roofs... We heard they were torn off many of the residences and buildings -- maybe 80 to 90 per cent of homes."
Maysak formed two weeks after Severe Tropical Cyclone Pam slammed into Vanuatu causing widespread damage and leaving 11 people dead in the South Pacific island nation.
The Philippines state weather forecaster said it was too early to say if the latest typhoon would likely affect the country but that it would reassess the situation when the storm entered its area of responsibility tomorrow or Thursday.