File:Dust off Arabian Peninsula (MODIS 2018-08-03).jpg

English: An expansive plume of dust from the Rub’ al Khali swept across the southeastern part of the Arabian Peninsula and over the Arabian Sea between July 28 and July 31, 2018. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of the swirling sand on July 31.

It is shamal season on the Arabian Peninsula. In the summer, a hot and dry, low-level northwesterly wind—the shamal—blows almost continuously, often stirring up huge clouds of sand and dust.

Reduced visibility posed serious risks in this dust storm. It caused hundreds of automobile and other accidents in Dubai, the largest city in the United Arab Emirates (UAE). Unusually high levels of particulates in the air also triggered warnings about allergies and respiratory health problems and led to increases in the number of people admitted to hospitals. Government health officials in several countries warned people to stay inside as much as possible and to cover their noses and mouths when walking outside.

While people living on the Arabian Peninsula have long monitored the shamal and even oriented ancient cities to the northwest to maximize the ventilation effect the wind would have on buildings, modern-day scientists are still working to define and quantify the shamal from a statistical perspective. One recent study reported that summer shamal winds usually begin on May 30, subside by August 16, and reach peak speeds each day around noon.