Jamaica: Macro-Socio-Economic and Environmental Assessment of ...

During this time, the effects of the hurricane were most pronounced over the island’s
southwestern parishes. The data also suggest that parishes in the northeast were relatively
unscathed by the heavy rainfall and violent winds associated with Ivan.
The Severe Weather Event
The Meteorological Service Division operates a Doppler radar that provides rainfall information
out to a radius of 480 kilometres from the radar station near Kingston. This equipment is also
capable of estimating wind speeds within its range. The Division also monitors a network of
over 250 rainfall stations across the island; each of which is required to record the accumulated
rainfall over each 24-hour period, from 7 a.m. that day to 7 a.m. the following day. This
facilitates a quantification of flooding events, estimation of return periods for such events, and
comparative analyses with prior events and established climatic averages.
Showers and thunderstorms, associated with the instability created by Ivan, began to impact
Jamaica on September 9, 2004 with morning showers over Portland and St. Thomas in the
extreme east of the country, and showers over Westmoreland and St. Elizabeth in the southwest
during the afternoon. The Doppler radar also detected moderate to heavy showers over
northeastern parishes during the afternoon of the 9 th .
Friday, September 10 began with scattered light to moderate showers being detected by the radar
over territorial waters to the north and south of the island. These came ashore in the northeast
and gradually spread along the north coast and then over eastern and central parishes during the
early hours of the morning. By mid-morning, rainfall was affecting sections of all parishes with
varying intensities; however, the heaviest activity appeared to have been occurring in the
northwest. During the afternoon, showers became more sustained as a spiral band covered
mainly the eastern half of the island and drifted westward.
Heavy rainfall and violent winds continued across the island and over adjacent waters throughout
September 11. Strongest wind speeds were estimated, by the radar, to be sustained at about 180
kilometres per hour. This was as the eye of Hurricane Ivan passed close to the island’s southern
coast, and satellite imagery also suggests that sections of southern parishes were directly affected
by the activity within the eyewall of the hurricane. Rainfall activity was also observed on the
12 th over most parishes but with decreasing intensity throughout the day.
The strongest winds actually recorded by meteorological equipment during Ivan’s passage were
214 km/h at the Pedro Bank, which is about 90 km off the south coast. Since the centre of the
system was somewhat closer to Portland Point, it could be assumed that winds of at least that
magnitude existed on the mainland. Each of the Service’s automatic weather stations located on
the mainland ceased recording at some point between September 10 and 12, hence, the highest
reported winds were not representative of what was experienced. The Doppler radar, however,
estimated that winds across the island were sustained at 180 km/h during the early hours of
September 11.
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