The first tropical storm of the 2003-2004 cyclone season had local meteorologists worried on Wednesday October 1, before it significantly weakened and turned its course away from Seychelles.

Tropical Storm “Abaimba,” which was officially confirmed and named at 4 a.m. on Wednesday, developed some 900 kilometres east of Mahe, but initial forecasts projected that the storm would   be only 300 kilometres away from Mahe on Sunday October 5.

Wills Agricole, the acting director of Seychelles Meteorological Services, said on Friday October 3, that the storm, which was at one point moving eastward towards Seychelles at 12 kilometres per hour, had considerably weakened and was reversing course, moving West and then South at a much slower pace of 4 kilometres an hour.

While the formation of tropical storms was previously an issue not taken seriously by Seychellois, Mr Agricole said last year’s tropical storm that affected Praslin has led meteorologists to pay much closer attention to storms that develop east of Seychelles and near the equator.

What is particularly troubling, he said, is that "Abaimba" appears to have formed under the same circumstances, and at nearly the same time, as the tropical storm that hit Praslin on September 7 last year.

Although "Abaimba" is no longer a threat, the storm marks another early start to this year’s cyclone season, which normally begins around November 1.  Whether this is part of a trend or simply a freak occurrence is something meteorologists will be studying carefully, Mr Agricole said. The 2002-2003 tropical cyclone season was a particularly long and active one.  It started early in September and ended late in May, which Mr Agricole said was quite abnormal.

A total of 13 named disturbances were formed last year and quite a few of them formed close to the Seychelles territorial waters.  Among the disturbances was the tropical storm that hit Praslin on September 7 last year.

Mr Agricole, who recently attended the 16th Regional Association 1 Tropical Cyclone Committee Meeting for the South West Indian Ocean in Maputo, Mozambique, said that it was confirmed during the meeting that a “macro-burst” that had developed within the tropical storm is what had caused extensive damage to areas of Praslin.

A macro-burst is a large downdraft with outburst winds extending in excess of 4 kilometres horizontally, causing widespread, tornado-like damage.

Evidence supporting the presence of a macro-burst, Mr Agricole said, included the isolation of the storm’s effects on Praslin and the pattern of fallen trees in some areas, which could indicate the swirling winds characteristic of a macro-burst.

“The fact that both Mahe and La Digue were unaffected by the strong winds would suggest that whatever hit Praslin was something of only a few kilometres across, which in fact was a macro-burst which had developed locally within the tropical storm,” Mr Agricole said.

LINKS