loo (wind)

{{Short description|Hot, summer wind}}

File:Loo Winds India Pakistan Map.jpg towards and through the Indo-Gangetic Plain of India and Pakistan]]The Loo is a strong, dusty, gusty, hot and dry summer wind from the west which blows over the Indo-Gangetic Plain region of North India and Pakistan.{{Citation | title=Essentials of Ecology and Environmental Science | author=S.V.S. Rana | year=2007 | publisher=Prentice Hall of India | isbn=978-81-203-3300-0 | url=https://books.google.com/books?id=IAPKG4LEBbQC | quote=... In the plains of northern India and Pakistan, sometimes a very hot and dry wind blows from the west in the months of May and June, usually in the afternoons. It is known as loo. Its temperature invariably ranges between (115°F-120°F) 45 °C and 50 °C (115°F-120°F). People, when exposed to loo ...}} It is especially strong in the months of May and June. Due to its very high temperatures (45 °C–50 °C or 115 °F–120 °F), exposure to it often leads to fatal heatstrokes.

Since it causes extremely low humidity and high temperatures, the Loo also has a severe drying effect on vegetation leading to widespread browning in the areas affected by it during the months of May and June.{{Citation | title=1001 Questions Answered About: Hurricanes, Tornadoes and Other Natural Air Disasters | author=Barbara Tufty | year=1987 | publisher=Dover Publications | isbn=0-486-25455-0 | url=https://books.google.com/books?id=0Ib4YZlSRXkC | quote=... This wind dries out crops and makes people fretful by its eerie singing ...}}

Origin and ending

The Loo mainly originates in the large desert regions of the northwestern Indian subcontinent: the Great Indian Desert, the Cholistan Desert and the desert areas of Southern Balochistan.{{Citation | title=Geography: Physical and Human | author=Phani Deka | year=2006 | publisher=New Age International | isbn=81-224-1912-7 | url=https://books.google.com/books?id=-C-1B9gk9s4C | quote=... In north India, the hot wind of Thar desert that blows during early summer is called Loo ...}}

The Loo ends in late summer, with the arrival of the Indian

monsoon. In some areas of North India and Pakistan, there are brief, but violent, dust storms known as Kali Andhi (or black Storm) before the monsoon sets in.{{Citation | title=Andhi (Kali Andhi) | publisher=WeatherOnline | access-date = 2009-06-21 | url=http://www.weatheronline.co.uk/reports/wind/The-Andhi.htm | quote=... The Kali Andhi, or black storm is a violent, squally dust storm {{sic|occ|uring}} in late spring in north-western India. The Andhi heralds the imminent arrival of the monsoon ...}} The arrival of monsoon clouds in any location is frequently accompanied with cloudbursts,{{Citation | title=Cloudburst washes away water mills in Himachal | publisher=Headlines India | access-date=2009-06-21 | date=2006-07-24 | url=http://www.headlinesindia.com/archive_html/24July2006_6957.html | quote=... A cloudburst in a remote Himachal Pradesh mountainous valley washed away several water-run mills, a bridge, a road and a large tract of farmland, but there were no reports of casualties ... | archive-url=https://archive.today/20130125010400/http://www.headlinesindia.com/archive_html/24July2006_6957.html | archive-date=2013-01-25 | url-status=dead }} and the sudden transformation of the landscape from brown to green can seem "astonishing" as a result of the ongoing deluge and the abrupt cessation of the Loo.{{Citation | title=India | author=John Strachey | publisher=K. Paul, Trench, Trübner & Co | year=1894 | url=https://books.google.com/books?id=7bI9AAAAIAAJ | quote=... At last, when the heat has become greater than ever, the clouds begin to collect, and there comes down a deluge, almost always accompanied by thunder and lightning ... nothing can be more wonderful than the change which comes almost instantaneously over the whole face of nature ... within a time that may be measured by hours rather than days, the country that was like a desert begins to look like a garden. The rapidity of the progress of vegetation is astonishing ...| author-link=John Strachey (civil servant) }}

Dwelling adaptation

Since the plains of North India and Pakistan are both very hot and extremely dry during this season, water evaporates quite readily. Although this leads to the drying out of many ponds and lakes, the extreme dryness of the air is also easily exploited to create evaporation-based cooling systems. Windows shielded with fiber-screens of the fragrant khas (ख़स/خس or vetiver) dry-grass that are kept damp with a simple water-pumping mechanism are quite effective as an inexpensive form of air conditioning, and have been in common use throughout the plain portions of the northern Indian subcontinent for centuries.{{Citation | title=The cultural heritage of Pakistan | author=Sheikh Mohamad Ikram| author2 = Thomas George Percival Spear | author-link2 = Percival Spear|year=1955 | publisher=Oxford University Press | url=https://books.google.com/books?id=4lXHAAAAIAAJ | quote=... He introduced the system of cooling water with the help of saltpetre, and invented the Khas-ki-Tatti, which has for centuries remained the Indian method of air-conditioning ...| author-link=S. M. Ikram}} Because evaporation proceeds at a very rapid rate in the extreme dryness, the cooling effect can be quite dramatic and result in dwellings where the interior feels chilly.{{Citation | title=Tashil-ul-Kalam, or Hindustani made easy | author=William Rice M. Holroyd | year=1873 | publisher=Oxford University | url=https://books.google.com/books?id=qbsOAAAAQAAJ | quote=... Khas, vulgarly khas-khas, a kind of grass from which screens or tattis are made, for use in the hot season. The tatti is placed in a doorway and kept perpetually wet; and the hot dry westerly wind, after being allowed to pass through it, becomes quite cold ...}} The water in the screens evaporates very rapidly, however, so it must constantly be replenished from raised tanks or with pumps (that can sometimes be driven by the Loo itself). Any water reservoir used must also be shielded from the Loo and the sun, or it can rapidly be depleted.

Ecological effects

Many birds and animals succumb to the Loo in the summer months, especially in deforested areas where the Loo blows unhindered and shelter is unavailable.{{Citation | title=Indian summer too hot for Cheetahs from Singapore | newspaper=India Gazette | date=2009-05-06 | access-date=2009-06-25 | url=http://story.indiadgazette.com/index.php/ct/9/cid/701ee96610c884a6/id/498269/cs/1/ | quote=... Authorities in the Shakkarbaug Zoo ... removed a pair of Cheetahs ... from public view as the animals could not bear the intense heat wave ... have been lodged in a ... temperature-controlled environment ... As many as 30 Cheetahs brought by various zoos in India ... died as they could not adjust to the harsh Indian climate during summer months ...}}{{Citation | title=A Handbook for Poultry Officers in India | author=Allan McArdle, J. N. Panda | year=1968 | publisher=UNICEF | url=https://books.google.com/books?id=XpkvAAAAYAAJ | quote=... bird losses hh they won't go out in the sun to drink, and then die in heat waves ...}} Certain insect-borne diseases, such as malaria, have historically registered dips during the Loo season as insects populations also plummet during this season. Even prior to the 1897 discovery that mosquitoes transmitted malaria, officials in Asia had noticed the strong winds in the plains of Northernmost India naturally made the region relatively free of the disease.{{cite book |last1=Oldham |first1=Charles Frederick |title=What is Malaria?: And why is it Most Intense in Hot Climates? An Enquiry Into the Nature and Cause of the So-called Marsh Poison, with Remarks on the Principles to be Observed for the Preservation of Health in Tropical Climates and Malarious Districts |date=1871 |publisher=Lewis |url=https://books.google.com/books?id=2FYXAQAAMAAJ&q=Charles+Frederick+Oldham+1871 |language=en| quote=... In the plains of upper India, sleeping out of doors is attended with but little danger, even for Europeans, in the dry, hot months; although, at other seasons, feer would be a probable result.. far outweigh all risk from "malaria." ...}}

References

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