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| Titel |
Meteorological, elevation, and slope effects on surface hoar formation |
| VerfasserIn |
S. Horton, M. Schirmer, B. Jamieson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 4 ; Nr. 9, no. 4 (2015-08-07), S.1523-1533 |
| Datensatznummer |
250116831
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| Publikation (Nr.) |
 copernicus.org/tc-9-1523-2015.pdf |
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| Zusammenfassung |
| Failure in layers of buried surface hoar crystals (frost) can cause hazardous
snow slab avalanches. Surface hoar crystals form on the snow surface and are
sensitive to micro-meteorological conditions. In this study, the role of
meteorological and terrain factors was investigated for three layers of
surface hoar in the Columbia Mountains of Canada. The distribution of
crystals over different elevations and aspects was observed on 20 days of
field observations during a period of high pressure. The same layers were
modelled over simplified terrain on a 2.5 km horizontal grid by forcing the
snow cover model SNOWPACK with forecast weather data from a numerical weather
prediction model. Modelled surface hoar growth was associated with warm air
temperatures, high humidity, cold surface temperatures, and low wind speeds.
Surface hoar was most developed in regions and elevation bands where these
conditions existed, although strong winds at high elevations caused some
model discrepancies. SNOWPACK simulations on virtual slopes systematically
predicted smaller surface hoar on south-facing slopes. In the field, a
complex combination of surface hoar and sun crusts were observed, suggesting
the simplified model did not adequately resolve the surface energy balance on
slopes. Overall, a coupled weather–snow cover model could benefit avalanche
forecasters by predicting surface hoar layers on a regional scale over
different elevation bands. |
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