Product Code Database
Example Keywords: blackberry -music $85-110
   » » Wiki: Orographic Lift
Tag Wiki 'Orographic Lift'.
Tag

lift occurs when an is forced from a low to a higher elevation as it moves over rising .

(2025). 9780888652836, University of British Columbia. .
As the air mass gains it quickly cools down adiabatically, which can raise the relative humidity to 100% and create and, under the right conditions, precipitation.

Orographic lifting can have a number of effects, including precipitation, rain shadowing, leeward winds, and associated clouds.


Precipitation
Precipitation induced by orographic lift occurs in many places throughout the world. Examples include:
  • The in central Arizona
  • The western slope of the Sierra Nevada range in California.
  • The western slope of the in Utah. Specifically the Little and Big Cottonwood Canyons.
  • The mountains near Baja California North – specifically La Bocana to .
  • The windward slopes of Khasi and Jayantia Hills (see ) in the state of in India.
  • The Western Highlands of Yemen, which receive by far the most rain in Arabia.
  • The that run along India's western coast.
  • The northern slopes of the leading to the , in , and Georgia.
  • The Great Dividing Range of Eastern and South Eastern Australia which forces cold, moist westerlies up the inland slopes, originating from the .
  • The mountains of , which face a prevailing flow off the .
  • The mountains of western which also face a prevailing westerly flow.
  • The southern , which face a prevailing westerly flow off the .
  • The mountains of the Chocó Department in , which face a prevailing westerly flow off the Pacific Ocean and are one of the wettest places on Earth.
  • The western uplands of , including the Grampian mountains, , , and which face a prevailing westerly flow off the .
  • The Northwestern United States and (, Washington, , and Southern ) see prevailing westerly flow off the northern . Places on the sea-facing side of coastal mountains see in excess of 140 inches (over 3.5 m) of precipitation per year. These locales are on the side of the which are in the path of systems, and therefore receive the moisture which is effectively squeezed from the clouds.

  • The region of New York and , particularly with lake effect snows.
  • Transylvania County, North Carolina, which gets the most rainfall of anywhere in the Eastern U.S. ().
  • The Appalachian Mountains in (particularly the western facing slopes).
  • The Eastern seaboard of .
  • , , . The cold Atlantic air mass flows up over the north western face to above sea level and is met by the warm Indian Ocean air mass from the south eastern back side of the mountain forming the famous "Table Cloth".
  • mountain area, .
  • In Colorado west of Denver maximum snowfall is recorded at relatively low elevations, around Idaho Springs, Genesee, Evergreen, and even as low as Golden and Castle Rock.


Rain shadowing
The highest precipitation amounts are found slightly upwind from the prevailing winds at the crests of mountain ranges, where they relieve and therefore the upward lifting is greatest. As the air descends the lee side of the mountain, it warms and dries, creating a rain shadow. On the lee side of the mountains, sometimes as little as 15 miles (25 km) away from high precipitation zones, annual precipitation can be as low as 8 inches (200 mm) per year.
(2025). 9780195132717, Oxford University Press.

Areas where this effect is observed include:

  • The block moisture from the
  • The in and
  • 's Rhone valley
  • Areas east of the in the Pacific Northwest (Washington and )
  • Areas east of the Olympic Mountains in Washington state, (i.e. Sequim, Washington)
  • The of the United States, east of the Sierra Nevada
  • Geography of the United States Pacific Mountain System
  • Pacific Cordillera
  • 's Central Valley
  • The Canadian Prairies
  • The leeward sides of the . The entire island of is in the rain shadow of
  • North East England is in the eastern rain shadow of the , due to Britain's prevailing wind coming from the South West. This explains the significant differences between the rainfall between North West and North East England. This impact also occurs to varying degrees to the east of the Grampian Mountains, in and along the England Wales borders and in to the east of .
  • The Central Coast, , , Monaro and the South Coast regions in Southeastern Australia in New South Wales; as snow-bearing westerlies arriving from the southwest (the Great Australian Bight) and up the ranges are forced upwind the inland slopes of the Great Dividing Range, the coastal plain remains dry and is significantly warmer than on the inland slopes at equivalent altitudes. This is evident when comparing on the windward slopes to on the leeward coastal plain, both around . Rain Shadows by Don White. Australian Weather News. Willy Weather. Retrieved 24 May 2021. Conversely, if the polar front or rain event arrives from the south-east (the ), then the coastal plain will be on the windward side and the inland slopes are on the leeward side. And the outlook for winter is … wet by Kate Doyle from The New Daily. Retrieved 24 May 2021.
  • The in the Land of Israel and the .
  • The Southern Alps of New Zealand


Leeward winds
Downslope winds occur on the leeward side of mountain barriers when a stable air mass is carried over the mountain by strong winds that increase in strength with height. Moisture is removed and latent heat released as the air mass is orographically lifted. As the air mass descends, it is compression heated. The warm , locally known as the , or or Nor'wester depending on the region, provide examples of this type of wind, and are driven in part by latent heat released by orographic-lifting-induced precipitation.

A similar class of winds, the , the Bora and Santa Ana winds, are examples where orographic lifting has limited effect since there is limited moisture to remove in the or other air masses; the Sirocco, Bora and Santa Ana are driven primarily by () compression heating.


Associated clouds
As air flows over mountain barriers, orographic lift can create a variety of cloud effects.
  • Orographic fog is formed as the air rises up the slope and will often envelope the summit. When the air is humid, some of the moisture will fall on the windward slope and on the summit of the mountain.
  • When wind is strong, a banner cloud is formed downwind of the upper slopes of isolated, steep-sided mountains. It is created by the low pressure areas in the downwind drawing in relatively humid air from the lower slopes of the mountain. This reduction in pressure compared to the surrounding air increases condensation, in the same manner as an aircraft's . The most famous such cloud forms routinely in the lee of the .

  • The leeward edge of an extensive mass of orographic clouds may be quite distinct. On the leeward side of the mountain, the air flowing downward is known as a . Because some of the moisture that has condensed on the top of the mountain has precipitated, the foehn (or föhn) is drier, and the lower moisture content causes the descending air mass to warm up more than it had cooled down during ascent. The distinct cut-off line which forms along and parallel to the ridge line is sometimes known as a foehn wall (or föhn wall). This is because the edge appears stationary and it often appears to have an abrupt wall-like edge. A foehn wall is a common feature along the of the .
  • A rotor cloud is sometimes formed downwind and below the level of the ridge. It has the appearance of the ragged type but it is caused by a turbulent horizontal vortex, i.e. the air is very rough.
  • are stationary lens-shaped clouds that are formed downwind of mountains by if the air mass is close to the dew point. They are normally aligned at right-angles to the wind direction and are formed at altitudes up to .
  • A cap cloud is a special form of the lenticular cloud with a base low enough that it forms around and covers the peak, capping it.
  • A chinook arch cloud is an extensive wave cloud. It has this special name in North America where it is associated with the . It forms above the mountain range, usually at the beginning of a chinook wind as a result of orographic lifting over the range. It appears when seen from downwind to form an arch over the mountain range. A layer of clear air separates it from the mountain.


See also

Page 1 of 1
1
Page 1 of 1
1

Account

Social:
Pages:  ..   .. 
Items:  .. 

Navigation

General: Atom Feed Atom Feed  .. 
Help:  ..   .. 
Category:  ..   .. 
Media:  ..   .. 
Posts:  ..   ..   .. 

Statistics

Page:  .. 
Summary:  .. 
1 Tags
10/10 Page Rank
5 Page Refs
2s Time