Depth hoar
File:Sugar snow - panoramio.jpg
Depth hoar, also called sugar snow{{cite web |url=https://www.powder.com/stories/the-safe-zone/aware-depth-hoar/ |title=Be Aware of Depth Hoar |work=Powder Magazine |date=15 April 2014 |access-date=April 15, 2014}} or temperature gradient snow (or TG snow),{{cite web |title=Depth Hoar |url=https://avalanche.org/avalanche-encyclopedia/depth-hoar/ |website=Avalanche.org |publisher=American Avalanche Association |access-date=6 March 2019}} are large snow-crystals occurring at the base of a snowpack that form when uprising water vapor deposits, or desublimates, onto existing snow crystals. Depth hoar crystals are large, sparkly grains with facets that can be cup-shaped and that are up to 10 mm in diameter. Depth hoar crystals bond poorly to each other, increasing the risk for avalanches.
The formation of depth hoar in Arctic or Antarctic firn can cause isotopic changes in the accumulating ice. This can influence analysis of ice cores in scientific research.
References
- {{cite journal|last1=Pfeffer|first1=W. T.|last2=Mrugala|first2=R.|year=2002|title=Temperature gradient and initial snow density as controlling factors in the formation and structure of hard depth hoar|journal=Journal of Glaciology|volume=48|issue=163|pages=485–494|doi=10.3189/S0022143000002008|doi-access=free}}
Further reading
- [http://www.montana.edu/earthsciences/OLD-facstaff/images_misc/marienthal.pdf Depth Hoar, Avalanches, And Wet Slabs: A Case Study Of The Historic March, 2012 Wet Slab Avalanche Cycle At Bridger Bowl, Montana]montana.edu.
- [https://agupubs.onlinelibrary.wiley.com/doi/10.1029/JZ067i006p02377 The formation rate of depth hoar J. C. Giddings E. LaChapelle], First published in June 1962.
External links
- [https://avalanche.org/avalanche-encyclopedia/snowpack/weak-layer/persistent-weak-layers/depth-hoar-basal-facets/ The Avalanche Encyclopedia], extensive summary with animation of formation process
{{Ice}}