Shamal (wind)

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A shamal overspreading Iraq

A shamal (Arabic: شمال‎, 'north') is a northwesterly wind blowing over Iraq and the Persian Gulf states (including Saudi Arabia and Kuwait), often strong during the day, but decreasing at night.[1] This weather effect occurs anywhere from once to several times a year, mostly in summer but sometimes in winter.[1] The resulting wind typically creates large sandstorms that impact Iraq, most sand having been picked up from Jordan and Syria.

Synoptic conditions[edit]

Summer Shamal[edit]

When a passing storm with a strong cold front passes over the mountains of Turkey, the leading edge of a mass of relatively cooler air kicks up dust and sand, sending it aloft. Temperatures at lower elevations still hover above 105 °Fahrenheit (42 °Celsius) during these events.[2] In Iran, where winter storms can bring heavy snow to the terrain, a layer of dust can settle onto the snowpack.[3]

Winter Shamal[edit]

A winter Shamal is associated with the strengthening of a high pressure over the peninsula after the passage of a cold front while a deep trough of low pressure maintains itself over areas east of the Persian Gulf.[1] This leads to strong northerly wind over the Persian Gulf for periods up to five days. They are associated with cold temperatures.

The places around the Middle East most likely to see the winter variety lie near Lavan Island, Halul Island, and Ras Rakan. They persist from 24 to 36 hours during the winter and occur as frequently as two to three times per month between December and February. A persistent three- to five-day event occurs only once or twice a winter, and is accompanied by very high winds and seas.[4]

Effects[edit]

Shamals normally last three to five days. Dust and sandstorm is several thousand feet deep. Wind speeds can reach up to 70 km/hr. Such events can impact health and transport, as visibility becomes limited, some flights get cancelled. Sand dunes build up on roads and require a lot of effort to remove. Some infrastructure such as street signs, become damaged by the Shamals.

Past example[edit]

A notable storm caused by a shamal covered Baghdad with sand on August 8, 2005, resulting in a closing of nearly all shops and public activity. The storm also overwhelmed Baghdad's Yarmuk Hospital, which treated more than a thousand people with respiratory distress.[5] From February 1 through February 4, 2008, there was a massive dust storm associated with a Shamal wind advected over the Arabian Sea. It was estimated that the leading edge of the dust storm moved at around 20 km/h, and at one point extended from Muqdisho, Somalia to Mumbai, India.[6] Dust from this storm received press from the sports media as it swept across the Dubai Desert Classic golf tournament, where Tiger Woods was playing.[7]

Some investigations have also reported that dust storms generated over west Asian regions during summer could alter regional circulation features affecting even the Indian summer monsoon rainfall.[8]

Miscellany[edit]

  • A question about this wind was part of the 2003 National Geographic Bee.[9]
  • Shamal Arabic word, meaning North, is a male name in Afghanistan/Kurdistan.
In Afghanistan/Kurdistan shamal means both 'wind' and 'North.'
  • A sandstorm caused by Shamal winds tore apart a Marines encampment on HBO's Generation Kill (TV series) about the 2003 invasion of Iraq.

See also[edit]

Notes[edit]

  1. ^ a b c El-Baz, Farouk; R.M. Makharita. Gordon and Breach Publishers (ed.). The Gulf War and the Environment. pp. 31–54, 178. ISBN 978-2-88449-100-6. Retrieved 2009-06-03.
  2. ^ Weather Corner: Desert wind pattern in Iraq to shift in next two months. Retrieved on 2006-12-09.
  3. ^ NASA Earth Observatory. Natural Hazards >> Dust & Smoke >> Shamal Winds Drive Middle East Dust Storm. Archived 2008-10-28 at the Wayback Machine Retrieved on 2006-12-09.
  4. ^ United States Navy. Appendix C: Wind Climatology of the Winter Shamal. Retrieved on 2006-12-09.
  5. ^ NASA Earth Observatory. New Images: Iraq Dust Storm. Archived 2006-10-10 at the Wayback Machine Retrieved on 2006-12-09.
  6. ^ Arabian Sea dust storm AVHRR images from Amato Evan website [1][permanent dead link].
  7. ^ Tiger Woods Battles Sand Storm to Lead at Dubai Desert Classic [2].
  8. ^ http://www.nature.com/ngeo/journal/v7/n4/full/ngeo2107.html
  9. ^ CNN. AMERICAN MORNING: Interview With National Geographic Bee Champion. Retrieved on 2006-12-09.

External links[edit]