The island of Madagascar, which was hit by Cyclone Elita back on the
29th of January, recently suffered a direct hit from Gafilo, a far more
powerful storm rated as an intense Category 5 Cyclone at the time it
made landfall on the island's northeast coastline. So far Gafilo has
left 7 dead, 18 missing and up to 100,000 homeless on Madagascar.
Gafilo began as a tropical depression back on the 29th of February 2004
in the central Indian Ocean south of Deigo Garcia in the Chagos
Archipelago. Two days later on the 2nd of March, it became a tropical
storm and continued moving west. Gafilo strengthened into a Category 1
cyclone the next day on the 3rd, and March 4th saw Gafilo continuing to
intensify with winds increasing to 85 knots (98 mph) as estimated by
the Joint Typhoon Warning Center. On the 5th, Gafilo began a cycle of
rapid deepening with winds increasing to 125 knots (144 mph) making it
a major Category 4 cyclone. It was now moving west-southwest headed
straight for Madagascar. The next day, on the 6th of March 2004,
Gafilo struck the northeast coast of Madagascar near to the town of
Antalaha as a Category 5 cyclone, the highest possible rating, its
sustained winds having further increased to an estimated 140 knots
(161 mph). Ninety-five percent of Antalaha was reported destroyed.
The Tropical Rainfall Measuring Mission (TRMM) satellite captured
numerous, impressive images of Cyclone Gafilo covering most of it's
life cycle as it traversed the western Indian Ocean. The first image (top left)
was taken at 8:15 UTC on 4 March 2004. It shows the horizontal
distribution of rain rates as seen from above by the TRMM satellite.
Rain rates in the center swath are from the TRMM Precipitation Radar
(PR), the first and only precipitation radar in space, and rain rates
in the outer swath are from the TRMM Microwave Imager (TMI). The
rain rates are overlaid on infrared (IR) data from the TRMM Visible
Infrared Scanner (VIRS). In this first image, TRMM shows Gafilo to
have a large, closed eye but only weak (blues) to moderate (green
areas) rain rates immediately surround the center. A large rainband
with some embedded heavier convection (darker red areas) wraps in
towards the eye from the storm's northwest quadrant. At the time,
Gafilo was already rated a Category 1 cyclone with winds estimated at
65 knots (75 mph). The next image (top right) taken at 17:10 UTC on March 5
reveals a very different looking Gafilo. The eye has become smaller,
and the surrounding eyewall is now composed almost entirely of heavy
(reds) to intense (darker reds) rain rates of up to 2-inches per hour.
Tropical cyclones act like large heat engines. Their fuel comes from
the transformation of water vapor in the atmosphere. As water vapor
condenses into the tiny cloud droplets that eventually form the
precipitation, heat is released. This heat, known as latent heat, is
what drives the storm's circulation. In general, the more heating
that occurs, the more intense the storm will become. This heating is
most effective in driving the storm if it is occurs near its center
as TRMM shows is the case shown here with Gafilo. At this time,
Gafilo was a powerful Category 4 storm with winds estimated at 125
knots (144 mph).
The third (bottom left) image was taken at 8:02 UTC March 6th as Gafilo was
approaching the coast of Madagascar and shows a tropical cyclone at
its most mature, intense stage. The storm now has a very tight, very
small eye with a nearly perfectly symmetrical eyewall containing a
near-uniform concentric ring of intense rain rates (dark reds). The
storm is now at Category 5, and the winds are at 140 knots (161 mph).
The final image (bottom right) shows Gafilo in the Mozambique Channel after the
storm had crossed the entire northern half of Madagascar. Taken at
7:47 UTC on the 8th, with the circulation having been disrupted by
land and topography and its supply of water vapor essentially cutoff,
the eye is now totally gone with no visible eyewall present. A large
rainband with a broad area of intense (dark reds) to moderate (green
areas) rain remains, extending from the central part of the Mozambique
Channel eastward into western Madagascar north of the storm's center.
Gafilo had now been downgraded to a tropical storm with remaining winds
estimated at 55 knots (63 mph).
TRMM is a joint mission between NASA and the Japanese space agency JAXA.