Geography

Caribbean Islands Table of Contents

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 26C in January to 32C in June. Diurnal ranges are usually no greater than 3C in most places, but temperatures dipping to 13C 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.

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Source: U.S. Library of Congress