A meteorologist in Guam says he has serious concerns for people in the small atolls of Fais and Ulithi in the Federated States of Micronesia, as Maysak becomes a supertyphoon today.
Derek Williams, from the National Weather Service in Guam, says Maysak is tracking further north of Yap than expected, but Fais and Ulithi atolls, to Yap's east, are in its "firing range".
He says it will become a supertyphoon with winds of up to 250 kilometres per hour, so he is urging the 800 people on Ulithi and 300 people on Fais to seek shelter.
"A lot of the structures, they'll blow right off, even before the eye reaches them, so we urge people to find sturdier shelter on these small atolls. They might get the full fledge and it would decimate those locations, because their infrastructure isn't as built up as the larger islands of Yap and Guam, so we're really concerned about them."
Derek Williams says another concern are the high tides and storm surge, as the atolls only rise 5-10 metres above sea level.
He says Typhoon Maysak should reach Fais at 6pm local time and Ulithi at 10pm, and Yap early tomorrow morning.