People in Guam and the Northern Marianas are bracing for Typhoon Mawar which is forecast to intensify to category 4 strength before it hits them on Wednesday.
Guam is under a state of emergency and the island of Rota in the Northern Marianas is also in the firing line for Mawar.
The US National Weather Service said on Tuesday morning gusts generated by the typhoon were expected to reach destructive wind speeds of over 300 kilometres per hour.
A spokesperson for the US National Weather Service in Guam, Brandon Aydletthas, advised residents to stock up and prepare.
"We have got a very serious situation developing for us," Aydletthas said on Tuesday morning.
"Right now, we're looking at Wednesday afternoon - we are going to be seeing torrential rains, significant flooding concerns, and significant coastal inundation," he said.
This morning the storm was located around 360 kilometres southeast of Guam.
Aydletthas advised those living in light material housing to move to emergency shelter, saying it would become a "very grim situation" for Guam over the next 24 to 36 hours.
The next intermediate advisory was expected from the US National Weather Service at 1100 Chamorro Standard time which is 1300 New Zealand time.
The previous advisory had a typhoon warning for Guam and Rota, with a tropical storm warning and typhoon watch for Saipan and Tinian.