Towards the end of every year tropical storm activity moves from the northern hemisphere to the southern hemisphere. The South Indian Ocean has already spawned three tropical storms including the unusually strong early season Cyclone Anais in October. Attention has now switched to the South Pacific Ocean and Cyclone Evan.

Evan formed near Fiji a few days ago and moved north-east as it strengthened. As it reached the equivalent of hurricane intensity (winds near 75 mph) it made landfall over Samoa close to the capital city of Apia. Although winds of this strength are not exceptional for a cyclone, first reports indicate considerable wind damage and flooding from a storm surge of 12-15 feet (3.5-4.5 m). This storm surge is of similar height to that experienced in New York City during ‘Superstorm’ Sandy in October.

Visible satellite image of Cyclone Evan on 12 December 2012

Although Samoa lies within the cyclone belt of the South Pacific Ocean, the island nation has been relatively storm free for many years. Cyclone Heta passed close by in 2003, but the last time Samoa received direct strikes from tropical storms was in 1997 and 1998 by storms named Tui and, coincidentally, Evan.

To make matters worse, Cyclone Evan is expected to become slow moving near Samoa and American Samoa, producing large amounts of rainfall, before turning back south-west. Latest forecasts suggest Evan will strengthen some more and could threaten a strike on Fiji early next week.

Regional warnings for Cyclone Evan are produced by the Fiji Meteorological Service. The Met Office routinely supplies predictions of cyclone tracks from its global forecast model to regional meteorological centres worldwide, which are used along with guidance from other models in the production of forecasts and guidance.

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