Nivation
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Nivation is the set of geomorphic processes associated with
snow patch A snow patch, is a geomorphological pattern of snow and firn accumulation which lies on the surface for a longer time than other seasonal snow cover. Snow patches are known by a wide range of synonymous terms including snowpatches, snow beds, snow ...
es. The primary processes are
mass wasting Mass wasting, also known as mass movement, is a general term for the movement of rock (geology), rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is no ...
and the freeze-and-thaw cycle, in which fallen
snow Snow consists of individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water througho ...
gets compacted into
firn __NOTOC__ Firn (; from Swiss German "last year's", cognate with ''before'') is partially compacted névé, a type of snow that has been left over from past seasons and has been recrystallized into a substance denser than névé. It is ice that ...
or
névé Névé is a young, granular type of snow which has been partially melted, refrozen and compacted, yet precedes the form of ice. This type of snow can contribute to glacier formation through the process of ''nivation''. Névé that survives a ...
. The importance of the processes covered by the term ''nivation'' with regard to the development of periglacial landscapes has been questioned by scholars, and the use of the term is discouraged. ''Nivation'' has come to include various subprocesses related to
snow patch A snow patch, is a geomorphological pattern of snow and firn accumulation which lies on the surface for a longer time than other seasonal snow cover. Snow patches are known by a wide range of synonymous terms including snowpatches, snow beds, snow ...
es which may be immobile or semi-permanent. These sub-processes include
erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
(if any) or initiation of erosion,
weathering Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no move ...
, and
meltwater Meltwater (or melt water) is water released by the melting of snow or ice, including glaciers, glacial ice, tabular icebergs and ice shelf, ice shelves over oceans. Meltwater is often found during early spring (season), spring when snow packs a ...
flow from beneath the snow patch. Weathered particles are moved downslope by creep,
solifluction Solifluction is a collective name for gradual processes in which a mass moves down a slope ("mass wasting") related to freeze-thaw activity. This is the standard modern meaning of solifluction, which differs from the original meaning given to i ...
and rill wash. Over time, this leads to the formation of nivation hollows which, when enlarged, can be the beginnings of a
cirque A (; from the Latin word ) is an amphitheatre-like valley formed by Glacier#Erosion, glacial erosion. Alternative names for this landform are corrie (from , meaning a pot or cauldron) and ; ). A cirque may also be a similarly shaped landform a ...
.


References

Erosion Snow {{Erosion-stub