Weather tracker: Super Typhoon Sinlaku threatens Mariana Islands

The Mariana Islands archipelago in the western Pacific, home to the US territories of Guam and the Northern Mariana Islands, are bracing for extreme weather early this week as Super Typhoon Sinlaku approaches.The system originated as a cluster of thunderstorms over the seas of Micronesia before strengthening into a tropical storm and then a typhoon on Friday and Saturday.Over the weekend, it began to push north-west while rapidly intensifying, with sustained winds reaching 150mph on Sunday. As the storm moves through the western Pacific islands early this week, it is forecast to strengthen rapidly with 165mph winds.A slight northward shift in its track makes a direct hit on Guam – the most populous island and westernmost territory of the US – unlikely. Instead, Saipan and Tinian are expected to bear the brunt of the most severe conditions.The National Weather Service in Guam has issued several warnings for the Mariana Islands. Sinlaku’s powerful winds, combined with forecast rainfall totals exceeding 300mm between Monday and Thursday, are expected to whip up hazardous seas and storm surges before the storm’s arrival. These are likely to be followed by flash flooding, mudslides and wind damage.While typhoons can occur at any time of year in this region, the peak season typically runs from June to November, making a typhoon of this intensity in April particularly unusual.With winds exceeding 130 knots (150mph), the Joint Typhoon Warning Center classifies Sinlaku as a super typhoon. If it were located over the North Atlantic, it would be classified as a category 4 hurricane, with the potential to rise to category 5 at its peak. The terms “typhoon”, “hurricane” and “cyclone” describe the same meteorological phenomenon – the terminology varies by region.The path of Cyclone Maila as it tore through the Pacific Islands last week. Photograph: Susie Dodds/AAPMeanwhile, in the South Pacific, shortly after Cyclone Maila struck Papua New Guinea last week, another weather system developed. Tropical Cyclone Vaianu formed on 5 April and moved south-eastwards, passing close to Fiji without making landfall. It was then reclassified as an extratropical cyclone – not due to weakening, as average winds still reached 65mph, but because of a change in its structure.As Vaianu passed over New Zealand, red warnings for strong winds were issued over the weekend. In some regions, gusts peaked at 80mph, leading to widespread power outages and evacuations. The storm also generated massive ocean swell that battered the north coast of New Zealand, where one buoy recorded an 11-metre wave.