Influence of snow depth distribution on surface roughness in alpine terrain: a multi-scale approach

Veitinger, Jochen; Sovilla, Betty; Purves, Ross S.

doi:10.5194/tc-8-547-2014

Cited by 34 publications

(37 citation statements)

References 32 publications

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“…However, for very strong and thick slabs, the column length should not be lower than 2 m in order to be able to still observe a possible arrest of the fracture due to slab tensile failure. If slab fracture is not observed in a PST for a column length of 2 m, fracture arrest is likely to be mainly driven by terrain and snowpack spatial variability and a 3D-terrain model including the snowpack might be required to evaluate where fracture arrest might occur (Veitinger et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Modeling of crack propagation in weak snowpack layers using the discrete element method

Gaume¹,

Herwijnen²,

Chambon

et al. 2015

The Cryosphere

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Abstract. Dry-snow slab avalanches are generally caused by a sequence of fracture processes including (1) failure initiation in a weak snow layer underlying a cohesive slab, (2) crack propagation within the weak layer and (3) tensile fracture through the slab which leads to its detachment. During the past decades, theoretical and experimental work has gradually led to a better understanding of the fracture process in snow involving the collapse of the structure in the weak layer during fracture. This now allows us to better model failure initiation and the onset of crack propagation, i.e., to estimate the critical length required for crack propagation. On the other hand, our understanding of dynamic crack propagation and fracture arrest propensity is still very limited.To shed more light on this issue, we performed numerical propagation saw test (PST) experiments applying the discrete element (DE) method and compared the numerical results with field measurements based on particle tracking. The goal is to investigate the influence of weak layer failure and the mechanical properties of the slab on crack propagation and fracture arrest propensity. Crack propagation speeds and distances before fracture arrest were derived from the DE simulations for different snowpack configurations and mechanical properties. Then, in order to compare the numerical and experimental results, the slab mechanical properties (Young's modulus and strength) which are not measured in the field were derived from density. The simulations nicely reproduced the process of crack propagation observed in field PSTs. Finally, the mechanical processes at play were analyzed in depth which led to suggestions for minimum column length in field PSTs.

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Section: Discussionmentioning

confidence: 99%

Modeling of crack propagation in weak snowpack layers using the discrete element method

Gaume¹,

Herwijnen²,

Chambon

et al. 2015

The Cryosphere

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show abstract

“…It is assumed that this may lead to a more uniform slab thickness and, in combination with reduced support from the bed surface, to potentially larger release area sizes -in particular for surface slabs (McClung, 2001;Simenhois and Birkeland, 2008). Further, Veitinger et al (2014) showed that the progressive smoothing of surface roughness can be captured by a multi-scale roughness parameter. So far, roughness is only incorporated in some approaches as a single-scale terrain parameter, often not reflecting the adequate scale of a given snow scenario.…”

Section: Terrain-snow Cover Interactionmentioning

confidence: 99%

“…In a shallow snowpack, terrain roughness can have a stabilising function, hindering the formation of continuous weak layers (Schweizer et al, 2003), as well as providing mechanical support to the snowpack (McClung, 2001). However, increasing snow accumulation is known to smooth out surface roughness (Veitinger et al, 2014), reducing snowpack variability in the surface layers (Mott et al, 2010) and the mechanical support of a slab (van Herwijnen and Heierli, 2009). In this case, the stabilising effects of terrain roughness disappear or even reverse (McClung and Schaerer, 2002), and the formation of continuous weak layers and slabs, which favours fracture propagation (Simenhois and Birkeland, 2008), is facilitated.…”

Section: Roughnessmentioning

confidence: 99%

“…The measure is well suited to capture the process of terrain smoothing of snow (Veitinger et al, 2014). Based on slope and aspect definitions, normal unit vectors of every grid cell of a digital elevation model (DEM) are decomposed into x, y and z components (Fig.…”

Section: Roughnessmentioning

confidence: 99%

“…Therefore, in this section we present a simple procedure to approximate winter terrain roughness from a DTM. In order to do so, we use earlier findings of Veitinger et al (2014), who showed that terrain smoothing processes are related to scale as a function of snow depth and snow depth variability. This relationship is used to evaluate whether we can relate the scale of terrain roughness to given snow cover scenarios; in other words, the following question is posed: is there an optimal scale related to snow depth and its variability?…”

Section: Integration Of Terrain Smoothingmentioning

confidence: 99%

See 2 more Smart Citations

Potential slab avalanche release area identification from estimated winter terrain: a multi-scale, fuzzy logic approach

Veitinger¹,

Purves

Sovilla³

2016

Nat. Hazards Earth Syst. Sci.

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Abstract. Avalanche hazard assessment requires a very precise estimation of the release area, which still depends, to a large extent, on expert judgement of avalanche specialists. Therefore, a new algorithm for automated identification of potential avalanche release areas was developed. It overcomes some of the limitations of previous tools, which are currently not often applied in hazard mitigation practice. By introducing a multi-scale roughness parameter, fine-scale topography and its attenuation under snow influence is captured. This allows the assessment of snow influence on terrain morphology and, consequently, potential release area size and location. The integration of a wind shelter index enables the user to define release area scenarios as a function of the prevailing wind direction or single storm events. A case study illustrates the practical usefulness of this approach for the definition of release area scenarios under varying snow cover and wind conditions. A validation with historical data demonstrated an improved estimation of avalanche release areas. Our method outperforms a slope-based approach, in particular for more frequent avalanches; however, the application of the algorithm as a forecasting tool remains limited, as snowpack stability is not integrated. Future research activity should therefore focus on the coupling of the algorithm with snowpack conditions.

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Snow instability patterns at the scale of a small basin

Reuter¹,

Schweizer²

2016

JGR Earth Surface

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Spatial and temporal variations are inherent characteristics of the alpine snow cover. Spatial heterogeneity is supposed to control the avalanche release probability by either hindering extensive crack propagation or facilitating localized failure initiation. Though a link between spatial snow instability variations and meteorological forcing is anticipated, it has not been quantitatively shown yet. We recorded snow penetration resistance profiles with the snow micropenetrometer at an alpine field site during five field campaigns in Eastern Switzerland. For each of about 150 vertical profiles sampled per day a failure initiation criterion and the critical crack length were calculated. For both criteria we analyzed their spatial structure and predicted snow instability in the basin by external drift kriging. The regression models were based on terrain and snow depth data. Slope aspect was the most prominent driver, but significant covariates varied depending on the situation. Residual autocorrelation ranges were shorter than the ones of the terrain suggesting external influences possibly due to meteorological forcing. To explore the causes of the instability patterns we repeated the geostatistical analysis with snow cover model output as covariate data for one case. The observed variations of snow instability were related to variations in slab layer properties which were caused by preferential deposition of precipitation and differences in energy input at the snow surface during the formation period of the slab layers. Our results suggest that 3-D snow cover modeling allows reproducing some of the snow property variations related to snow instability, but in future work all relevant micrometeorological spatial interactions should be considered.

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Influence of snow depth distribution on surface roughness in alpine terrain: a multi-scale approach

Cited by 34 publications

References 32 publications

Modeling of crack propagation in weak snowpack layers using the discrete element method

Modeling of crack propagation in weak snowpack layers using the discrete element method

Potential slab avalanche release area identification from estimated winter terrain: a multi-scale, fuzzy logic approach

Snow instability patterns at the scale of a small basin

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