Khamsin

Khamsin in hieroglyphs
Resetyu Rstyw The south winds
Dust storm over Libya (NASA/EOS)

Khamsin,^[1] chamsin or hamsin (Arabic: خمسين ḫamsīn, meaning "fifty"), more commonly known in Egypt and Palestine as khamaseen (Egyptian Arabic: خماسين ḫamāsīn, IPA: [xɑmæˈsiːn] ^ⓘ), is a dry, hot, sandy local wind affecting Egypt and the Levant; similar winds, blowing in other parts of North Africa, the Arabian Peninsula^{[citation needed]} and the entire Mediterranean basin, have different local names, such as bad-i-sad-o-bist roz in Iran and Afghanistan, haboob in the Sudan, aajej in southern Morocco, ghibli in Tunis, harmattan in the western Maghreb, africo in Italy, sirocco (derived from the Arabic šarqiyya, "eastern") which blows in winter over much of the Middle East,^[2] and simoom.^{[citation needed]}

From the Arabic word for "fifty", these dry, sand-filled windstorms blow sporadically in Egypt typically after fifty days from the start of spring, hence the name. The term is also used in the southern Levant (Palestine, Jordan), where the phenomenon takes a partly different form and blows both during spring and autumn.^[2]

When the storm passes over an area, lasting for several hours, it carries great quantities of sand and dust from the deserts, with a speed up to 140 kilometers per hour (87 mph; 76 knots), and the humidity in that area drops below 5%. Even in winter, the temperatures rise above 45 °C (113 °F) due to the storm. The sand storms are reported to have seriously impeded both Napoleon's military campaigns in Egypt as well as Allied-German fighting in North Africa in World War II.^{[citation needed]}

In the southern Levant it takes the shape of an oppressive weather front with hot temperatures, large quantities of dust impeding visibility, and strong winds during the night.^[2] In the Book of Exodus of the Hebrew Bible, the ruah kadim (‏רוח קדים‎) or "east wind" is the cause of the parting of the Red Sea (Exodus 14:21).^[2]