The leeward slopes, however, exhibit a characteristic rain-shadow effect that produces desert conditions, and the sparse shrub cover almost disappears.
The leeward slopes receive substantially less from 20 to 40 inches.
In the lee of the Southern Alps, where the effect of the foehn (a warm, dry wind of leeward mountain slopes) is marked, humidity can become very low.
In addition, the flow of wind past the building produces vortices near the corners on the leeward side; these vortices are unstable and every minute or so they break away downwind, alternating from one side to another.
Lee cyclone, small-scale cyclone that forms on the leeward, or downwind, side of mountain barriers as the general westerly flow is disturbed by the mountain.
These forests are found in regions of Yukon and Alaska that occur on the leeward side of mountains which are sheltered from moisture-bearing winds, as well as in some portions of the interior of the Far East region of Russia.
Some are located leeward, where it is calm and sheltered for example, Cat Island.
Thus, they commonly form on the more protected leeward end of the reef.
On the Caribbean slopes of the Tabasará Mountains, which face the rain-bearing trade winds, average rainfall is approximately twice as heavy as on the leeward Pacific slopes.
It averages about 80 inches (2,000 mm) on Rarotonga, though with considerable difference between the windward and leeward sides of the central mountains; precipitation is slightly lower on Aitutaki and slightly higher on Penrhyn.
Wheat is the most widely cultivated crop, followed by rice and various types of millets, which are planted on the drier leeward slopes.
