Shamal (wind)

A shamal is a summer northwesterly wind blowing over Iraq and the Persian Gulf states (including Saudi Arabia and Kuwait), often strong during the day, but decreasing at night. [Golden Gate Weather Services. [http://ggweather.com/winds.html Names of Winds.] Retrieved on 2006-12-09.] This weather effect occurs anywhere from once to several times a year. The resulting wind typically creates large sandstorms that impact Iraq, although most sand is picked up from Jordan and Syria.

ynoptic setup

When a passing storm with a strong cold front passes over the mountains of Turkey and Kurdistan, 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. [ [http://ggweather.com/archive/weacornerapr08.htm Weather Corner: Desert wind pattern in Iraq to shift in next two months.] Retrieved on 2006-12-09.] In Iran, where winter storms can bring heavy snow to the terrain, a layer of dust can settle onto the snowpack. [NASA Earth Observatory. [http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=12690 Natural Hazards >> Dust & Smoke >> Shamal Winds Drive Middle East Dust Storm.] Retrieved on 2006-12-09.]

Climatology

Shamals result from strong northwest winds that are funnelled into the Persian Gulf by the mountains of Turkey and Iraq to the northeast and the high plains of Saudi Arabia to the southwest. The winds most commonly are strongest in the Spring to Summer and hence the Shamal events are as well, although they can occur at any time of year. During that time of year the polar jest stream to the north moves southward to become in close proximity to the subtropical jet to the south. The proximity of the two jet streams promotes the formation of strong but often dry cold fronts which create the Shamal. The strong winds of the Shamal form in front of and behind the front. Iraq typically experiences strong wind-driven dust 20 to 50 days per year [ [http://www.magazine.noaa.gov/stories/mag86.htm DUST STORMS, SAND STORMS AND RELATED NOAA ACTIVITIES IN THE MIDDLE EAST.] Retrieved on 2008-07-21.] .

According to folklore, the first major shamal occurring around May 25 is known as the Al-Haffar, or driller, since it drills huge depressions in desert sand dunes. The second, arriving in early June, coincides with the dawn star, Thorayya (Pleiades), and is therefore named Barih Thorayya. During this event, which is more violent than the others, fishermen usually remain in port because ancient folklore tells them that this wind devours ships. Near the end of June, the last shamal arrives, known as the Al-Dabaran. It is violent and continues for several days. Local residents keep doors and windows firmly shut as this shamal includes an all-penetrating fine dust which gets into everything. [DataDubai. [http://www.datadubai.com/technical-info/facts/climate/ Climate: March 16 2006.] Retrieved on 2006-12-09.]

Rare winter cases

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. [United States Navy. [http://www.nrlmry.navy.mil/forecaster_handbooks/WinterShamal/Winter%20Shamal%20in%20the%20Persian%20Gulf%20Appendix%20C.pdf Appendix C: Wind Climatology of the Winter Shamal.] Retrieved on 2006-12-09.]

Effects

Shamals normally last three to five days. Since the resultant dust and sandstorm is several thousand feet deep, travel by air and ground comes to a standstill. When they spread to nearby bodies of water, fishing and shipping become equally difficult. During these wind events, several Southwest Asia international airports have recorded winds as high as 49 mph (43 knots) which can drive dust over large distances downwind. [NOAA Magazine. [http://www.magazine.noaa.gov/stories/mag86.htm DUST STORMS, SAND STORMS AND RELATED NOAA ACTIVITIES IN THE MIDDLE EAST.] Retrieved on 2006-12-09.] The sandblasting effect has been reported to strip the paint off of cars [http://www.met.gov.kw/Climate/mohd/ht.php] [http://horizons1325.com/history/1990s/desert_storm/judy-2.html] .

Past example

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. [NASA Earth Observatory. [http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16997 New
] Retrieved on 2006-12-09.] From February 1 through February 4 2008, there was a massive dust storm associated with a Shamal wind advected over the Arabain Sea. It was estimated that the leading edge of the dust storm moved at around 20km/hr, and at one point extended from Muqdisho, Somalia to Mumbai, India. [Arabian Sea dust storm AVHRR images from Amato Evan website [http://cimss.ssec.wisc.edu/clavr/amato/Amato_T_Evan/Arabian_0208.html] .] . 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. [Tiger Woods Battles Sand Storm to Lead at Dubai Desert Classic [http://www.bloomberg.com/apps/news?pid=20601079&sid=adlQcWNi8aZw&refer=home] .]

Trivia

A question about this wind showed up in the 2003 National Geographic Bee. [CNN. [http://transcripts.cnn.com/TRANSCRIPTS/0305/22/ltm.16.html AMERICAN MORNING: Interview With National Geographic Bee Champion.] Retrieved on 2006-12-09.] Also Shamal is a male name in afghanistan, Shamal means Wind.

A sandstorm caused by Shamal winds tears apart a Marines encampment HBO's Generation Kill (TV series) about the 2003 invasion of Iraq.

ee also

*Dust storm or Sandstorm

References

External links

* [http://ggweather.com/winds.html Names of Winds]