The Red Sea, Arabic Al-Baḥr Al-Aḥmar, narrow strip of water extending southeastward from Suez, Egypt, for about 1,200 miles (1,930 km) to the Bab el-Mandeb Strait, which connects with the Gulf of Aden and thence with the Arabian Sea. Geologically, the Gulfs of Suez and Aqaba (Elat) must be considered as the northern extension of the same structure. The sea separates the coasts of Egypt, Sudan, and Eritrea to the west from those of Saudi Arabia and Yemen to the east. Its maximum width is 190 miles, its greatest depth 9,974 feet (3,040 meters), and its area approximately 174,000 square miles (450,000 square km).
The Red Sea contains some of the world’s hottest and saltiest seawater. With its connection to the Mediterranean Sea via the Suez Canal, it is one of the most heavily traveled waterways in the world, carrying maritime traffic between Europe and Asia. Its name is derived from the color changes observed in its waters. Normally, the Red Sea is an intense blue-green; occasionally, however, it is populated by extensive blooms of the algae Trichodesmium erythraeum, which, upon dying off, turn the sea a reddish-brown color.
The Red Sea region receives very little precipitation in any form, although prehistoric artifacts indicate that there were periods with greater amounts of rainfall. In general, the climate is conducive to outdoor activity in fall, winter, and spring—except during windstorms—with temperatures varying between 46 and 82 °F (8 and 28 °C). Summer temperatures, however, are much higher, up to 104 °F (40 °C), and relative humidity is high, rendering vigorous activity unpleasant. In the northern part of the Red Sea area, extending down to 19° N, the prevailing winds are north to northwest. Best known are the occasional westerly, or “Egyptian,” winds, which blow with some violence during the winter months and generally are accompanied by fog and blowing sand. From latitude 14° to 16° N the winds are variable, but from June through August strong northwest winds move down from the north, sometimes extending as far south as the Bab el-Mandeb Strait; by September, however, this wind pattern retreats to a position north of 16° N. South of 14° N the prevailing winds are south to southeast.
Physiography and submarine morphology
The Red Sea lies in a fault depression that separates two great blocks of Earth’s crust—Arabia and North Africa. The land on either side, inland from the coastal plains, reaches heights of more than 6,560 feet above sea level, with the highest land in the south.
At its northern end, the Red Sea splits into two parts, the Gulf of Suez to the northwest and the Gulf of Aqaba to the northeast. The Gulf of Suez is shallow—approximately 180 to 210 feet deep—and it is bordered by a broad coastal plain. The Gulf of Aqaba, on the other hand, is bordered by a narrow plain, and it reaches a depth of 5,500 feet. From approximately 28° N, where the Gulfs of Suez and Aqaba converge, south to a latitude near 25° N, the Red Sea’s coasts parallel each other at a distance of roughly 100 miles apart. There the seafloor consists of the main trough, with a maximum depth of some 4,000 feet, running parallel to the shorelines.