Item: Examining the Slope Scale Spatial Variability of Extended Column Test Results
-
-
Title: Examining the Slope Scale Spatial Variability of Extended Column Test Results
Proceedings: International Snow Science Workshop 2014 Proceedings, Banff, Canada
Authors:
- Ian Hoyer [ Snow and Avalanche Laboratory, Montana State University, Bozeman, MT, USA ]
- Jordy Hendrikx [ Snow and Avalanche Laboratory, Montana State University, Bozeman, MT, USA ]
- Karl W. Birkeland [ Snow and Avalanche Laboratory, Montana State University, Bozeman, MT, USA ] [ USDA Forest Service National Avalanche Center, Bozeman, MT, USA ]
Date: 2014-09-29
Abstract: Though a significant amount of research examines the spatial variability of snow stability at the slope scale, most of that work focuses on tests primarily related to fracture initiation. The small number of studies examining the spatial variability of fracture propagation (utilizing tests such as the ex-tended column test (ECT)) are inconsistent. Some work reports homogenous ECT results, while later studies showed more variable and difficult to explain results. Because of these inconsistencies, we measured the spatial variability ECT results on multiple slopes in southwest Montana over the course of two winters. We sampled 23 grids, with each grid containing 28 ECTs for a total of 644 ECTs using a pre-defined semi-random 30m by 30m extent. We tested slopes with a variety of weak layers (surface hoar, depth hoar, new snow, and near surface facets), slab characteristics (slab hardness, slab depth), and snow depths. Further, we sampled during varying levels of forecasted regional avalanche danger. Our data demonstrate that considerable spatial variability in ECT potential exists on many slopes, even with-out substantial variation in snowpack structure. When the regional avalanche danger is either considera-ble or low, results are likely to be more consistent, but when the regional danger is moderate, results tend to be more variable. Further, the ratio of ECTPs to ECTNs can be correlated with the forecasted danger level. The practical implications of our results are that ECTs, like all other stability tests, should be inter-preted with an appropriate level of caution.
Object ID: ISSW14_paper_P2.29.pdf
Language of Article: English
Presenter(s):
Keywords: Extended Column Test, Spatial variability, Stability evaluation, Propagation.
Page Number(s): 806-809
-