What is the common characteristics of a downslope wind?
A wind directed down a slope, often used to describe winds produced by processes larger in scale than the slope. Because this flow produces subsidence, downslope winds experience warming, drying, increasing stability, and clearing if clouds are present.
What is downslope flow?
A thermally driven wind directed down a mountain slope and usually occurring at night; part of the along-slope wind system.
What is downslope warming?
Downsloping is the process that occurs when a stream of air is forced to descend a mountain. As the air descends, it undergoes a series of changes that result in a warming/drying effect. This series of changes is known as adiabatic warming.
What are drainage winds?
Cold-air-runoff winds that are produced when air in contact with terrain surfaces is cooled and flows downslope and/or downvalley. Over even gently sloping topography, drainage winds also refer to gravity winds that drain cold air into frost hollows, river valleys, and other lower-lying terrain. …
What are the two types of katabatic winds?
Warm, dry katabatic winds occur on the lee side of a mountain range situated in the path of a depression. Examples for these descending, adiabatically warmed katabatic winds are the Foehn winds. Cold and usually dry katabatic winds, like the Bora, result from the downslope gravity flow of cold, dense air.
Can you describe a katabatic wind?
Katabatic wind, also called downslope wind, or gravity wind, wind that blows down a slope because of gravity. It occurs at night, when the highlands radiate heat and are cooled. This process is most pronounced in calm air because winds mix the air and prevent cold pockets from forming.
What causes a debris flow?
Debris flows can be triggered in a number of ways. Typically, they result from sudden rainfall, where water begins to wash material from a slope, or when water removed material from a freshly burned stretch of land. Another major cause of debris flows is the erosion of steams and riverbanks.
What is flows in mass wasting?
Flow – The debris is moving downslope as a viscous fluid. A mudflow is a flowing mixture of debris and water, usually moving down a channel. Slump – involves movement along a curved surface, the upper part moving downward while the lower part moves outward.
Are katabatic winds cold?
A katabatic wind originates from radiational cooling of air atop a plateau, a mountain, glacier, or even a hill. In Antarctica, by contrast, the wind is still intensely cold.
Why are downslope winds warm?
As these brisk winds come across the Rocky Mountains, air is rising to move over the higher terrain. As the air rises, the moisture is squeezed out of the parcel of air, which leaves it very dry at the summit. This dry, cooled air then sinks down the lee side of the mountains and warms adiabatically.
What is the definition of a downslope wind?
Downslope wind. Downslope wind- Air that descends an elevated plain and consequently warms and dries. Occurs when prevailing wind direction is from the same direction as the elevated terrain and often produces fair weather conditions.
Which is the best downsloping wind prog to use?
For the best downslope effect, the wind direction will be nearly perpendicular to the mountain chain and the winds will be fairly strong. A strong downsloping wind will show negative vertical velocities on the 700 millibar forecast prog.
When does a downsloping wind occur in a mountain chain?
A downsloping wind occurs as air traverses a mountain chain. For the best downslope effect, the wind direction will be nearly perpendicular to the mountain chain and the winds will be fairly strong.
Are there any downslope winds that are katabatic?
Not all downslope winds are katabatic. For instance, winds such as the föhn and chinook are rain shadow winds where air driven upslope on the windward side of a mountain range drops its moisture and descends leeward drier and warmer.