People in Guam and the Northern Marianas moved to emergency evacuation centers and made last-minute preparations on Sunday, hours before a "super typhoon" was projected to bulldoze through the US Pacific territories.

Super Typhoon Bavi was forecast to roar westwards over the area from early Monday with winds of 260 kilometers per hour (kph) – equivalent to a category 5 hurricane – and gusts of up to 315 kph.

The US National Weather Service (NWS) called the typhoon "very dangerous", warning of "tropical storm force" winds from Sunday afternoon or evening and "catastrophic" damage near the system's center later.

"Significant flooding from torrential rains, and coastal inundation are expected," the NWS said, with projected waves of up to 10.7 meters – the height of a 10-story building – creating "extremely dangerous" conditions at sea.

El Nino

The world's oceans experienced their hottest June on record and could set fresh highs in the months ahead, the European Union's Copernicus Marine Service said on Wednesday.

Warmer oceans help tropical storms to intensify and add more moisture, which can fall as heavy rain.

The World Meteorological Organization warned on Friday that El Nino, which typically occurs every two to seven years and lasts nine to 12 months, has already begun in the tropical Pacific and is likely to be strong.

The natural climate phenomenon warms surface temperatures in the central and eastern equatorial Pacific Ocean, bringing worldwide changes in winds, pressure and rainfall patterns.