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Caribbean Islands Geography
Geographically, Dominica is distinctive in many ways. The
country has one of the most rugged landscapes in the Caribbean,
covered by a largely unexploited, multi-layered rain forest. It is
also among the earth's most rain-drenched lands, and the water
runoff forms cascading rivers and natural pools. The island, home
to rare species of wildlife, is considered by many as a beautiful,
unspoiled tropical preserve. According to a popular West Indian
belief, Dominica is the only New World territory that Columbus
would still recognize.
Dominica is the largest and most northerly of the Windward
Islands. The island faces the Atlantic Ocean to the east and the
Caribbean Sea to the west. Its nearest neighbors are the French
islands of Guadeloupe, some forty-eight kilometers north, and
Martinique, about forty kilometers south. Oblong-shaped and
slightly smaller than New York City, Dominica is 750 square
kilometers in area, 47 kilometers in length, and 29 kilometers in
width. Roseau, the nation's capital and major port, is favorably
situated on the sheltered, southwestern coast.
Geologically, Dominica is part of the rugged Lesser Antilles
volcanic arc. The country's central spine, a northwest-southeast
axis of steep volcanic slopes and deep gorges, generally varies in
elevation from 300 meters to 1,400 meters above sea level. Several
east-west trending mountain spurs extend to the narrow coastal
plain, which is studded with sea cliffs and has level stretches no
wider than 2,000 meters. The highest peak is Morne Diablatins, at
1,447 meters; Morne Trois Pitons, with an elevation of 1,423
meters, lies farther south and is the site of the national park.
Dominica's rugged surface is marked by its volcanic past. Rock
formations are mainly volcanic andesite and rhyolite, with fallen
boulders and sharp-edged protrusions peppering slope bases. The
light- to dark-hued clayey and sandy soils, derived from the rocks
and decomposed vegetation, are generally fertile and porous. Only
a few interior valleys and coastal strips are flat enough for soil
accumulations of consequence, however. Although scores of mostly
mild seismic shocks were recorded in 1986, volcanic eruptions
ceased thousands of years ago. Sulfuric springs and steam vents,
largely concentrated in the central and southern parts of the
island, remain active, however. One of the largest springs, Boiling
Lake, is located in the national park.
Dominica is water-rich with swift-flowing highland streams,
which cascade into deep gorges and form natural pools and crater
lakes. The streams are not navigable, but many are sources of
hydroelectric power. Trafalgar Falls, located near the national
park, is one of the most spectacular sites on the island. The
principal rivers flowing westward into the Caribbean are the Layou
and the Roseau, and the major one emptying eastward into the
Atlantic is the Toulaman. The largest crater lake, called Boeri, is
located in the national park.
Dominica has a tropical wet climate with characteristically
warm temperatures and heavy rainfall. Excessive heat and humidity
are tempered somewhat by a steady flow of the northeast trade
winds, which periodically develop into hurricanes. The steep
interior slopes also alter temperatures and winds. Temperature
ranges are slight. Average daytime temperatures generally vary from
26°C in January to 32°C in June. Diurnal ranges are usually
no
greater than 3°C in most places, but temperatures dipping to
13°C
on the highest peaks are not uncommon.
Most of the island's ample supply of water is brought by the
trade winds. Although amounts vary with the location, rain is
possible throughout the year, with the greatest monthly totals
recorded from June through October. Average yearly rainfall along
the windward east coast frequently exceeds 500 centimeters, and
exposed mountainsides receive up to 900 centimeters, among the
highest accumulations in the world. Totals on the leeward west
coast, however, are only about 180 centimeters per year. Humidities
are closely tied to rainfall patterns, with the highest values
occurring on windward slopes and the lowest in sheltered areas.
Relative humidity readings between 70 percent and 90 percent have
been recorded in Roseau.
Hurricanes and severe winds, most likely to occur during the
wettest months, occasionally are devastating. The most recent
hurricanes of note were David and Frederick in August 1979 and
Allen in August l980. The 1979 hurricanes caused over 40 deaths,
2,500 injuries, and extensive destruction of housing and crops.
Many agricultural commodities were destroyed during the 1980 storm,
and about 25 percent of the banana crop was demolished by strong
winds in 1984.
Data as of November 1987
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