From AMS Glossary
(Many variant spellings.) A strong, dry, dust-laden desert wind that blows in the Sahara, Palestine, Jordan, Syria, and the desert of Arabia.
Its temperature may exceed 54°C and the humidity may fall below 10%. The name means "poison wind" and is given because the sudden onset of a simoom may cause heat stroke. This is attributed to the fact that the hot wind brings more heat to the body than can be disposed of by the evaporation of perspiration.