کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4675909 1634480 2012 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
A field study on failure of storm snow slab avalanches
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
A field study on failure of storm snow slab avalanches
چکیده انگلیسی

Storm snow often avalanches before crystals metamorphose into faceted or rounded shapes, which typically occurs within a few days. We call such crystals nonpersistent, to distinguish them from snow crystals that persist within the snowpack for weeks or even months. Nonpersistent crystals can form weak layers or interfaces that are common sources of failure for avalanches. The anticrack fracture model emphasizes collapse and predicts that triggering is almost independent of slope angle, but this prediction has only been tested on persistent weak layers. In this study, dozens of stability tests show that both nonpersistent and persistent crystals collapse during failure, and that slope angle does not affect triggering (although slope angle determines whether collapse leads to an avalanche). Our findings suggest that avalanches in storm snow and persistent weak layers share the same failure mechanism described by the anticrack model, with collapse providing the fracture energy. Manual hardness measurements and near-infrared measurements of grain size sometimes showed thin weak layers of softer and larger crystals in storm snow, but often showed failures at interfaces marked by softer layers above and harder layers below. We suggest collapse often occurs in crystals at the bottom of the slab. Planar crystals such as sectored plates were often found in failure layers, suggesting they are especially prone to collapse.


► Slope angle did not affect triggering of fracture in storm snow.
► Nonpersistent and persistent snow crystals collapsed when they failed.
► Planar crystals, such as sectored plates, were commonly found at fractures in new snow.
► Storm snow often failed at an interface, above a harder layer.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cold Regions Science and Technology - Volumes 79–80, August 2012, Pages 20–28
نویسندگان
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