Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties
If a weak snow layer below a cohesive slab is present in the snow cover, unstable snow conditions can prevail for days or even weeks. We monitored the temporal evolution of a weak layer of faceted crystals as well as the overlaying slab layers at the location of an automatic weather station in the S...
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ftethz:oai:www.research-collection.ethz.ch:20.500.11850/619925 2023-07-30T04:07:14+02:00 Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties Schweizer, Jürg id_orcid:0 000-0001-5076-2968 Reuter, Benjamin van Herwijnen, Alec Richter, Bettina Gaume, Johan id_orcid:0 000-0001-8931-752X 2016-11-11 application/application/pdf https://hdl.handle.net/20.500.11850/619925 https://doi.org/10.3929/ethz-b-000619925 en eng Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-10-2637-2016 http://hdl.handle.net/20.500.11850/619925 doi:10.3929/ethz-b-000619925 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 Unported The Cryosphere, 10 (6) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2016 ftethz https://doi.org/20.500.11850/61992510.3929/ethz-b-00061992510.5194/tc-10-2637-2016 2023-07-16T23:49:26Z If a weak snow layer below a cohesive slab is present in the snow cover, unstable snow conditions can prevail for days or even weeks. We monitored the temporal evolution of a weak layer of faceted crystals as well as the overlaying slab layers at the location of an automatic weather station in the Steintälli field site above Davos (Eastern Swiss Alps). We focussed on the crack propagation propensity and performed propagation saw tests (PSTs) on 7 sampling days during a 2-month period from early January to early March 2015. Based on video images taken during the tests we determined the mechanical properties of the slab and the weak layer and compared them to the results derived from concurrently performed measurements of penetration resistance using the snow micro-penetrometer (SMP). The critical cut length, observed in PSTs, increased overall during the measurement period. The increase was not steady and the lowest values of critical cut length were observed around the middle of the measurement period. The relevant mechanical properties, the slab effective elastic modulus and the weak layer specific fracture, overall increased as well. However, the changes with time differed, suggesting that the critical cut length cannot be assessed by simply monitoring a single mechanical property such as slab load, slab modulus or weak layer specific fracture energy. Instead, crack propagation propensity is the result of a complex interplay between the mechanical properties of the slab and the weak layer. We then compared our field observations to newly developed metrics of snow instability related to either failure initiation or crack propagation propensity. The metrics were either derived from the SMP signal or calculated from simulated snow stratigraphy (SNOWPACK). They partially reproduced the observed temporal evolution of critical cut length and instability test scores. Whereas our unique dataset of quantitative measures of snow instability provides new insights into the complex slab-weak layer interaction, it also ... Article in Journal/Newspaper The Cryosphere ETH Zürich Research Collection |
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Open Polar |
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ETH Zürich Research Collection |
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ftethz |
language |
English |
description |
If a weak snow layer below a cohesive slab is present in the snow cover, unstable snow conditions can prevail for days or even weeks. We monitored the temporal evolution of a weak layer of faceted crystals as well as the overlaying slab layers at the location of an automatic weather station in the Steintälli field site above Davos (Eastern Swiss Alps). We focussed on the crack propagation propensity and performed propagation saw tests (PSTs) on 7 sampling days during a 2-month period from early January to early March 2015. Based on video images taken during the tests we determined the mechanical properties of the slab and the weak layer and compared them to the results derived from concurrently performed measurements of penetration resistance using the snow micro-penetrometer (SMP). The critical cut length, observed in PSTs, increased overall during the measurement period. The increase was not steady and the lowest values of critical cut length were observed around the middle of the measurement period. The relevant mechanical properties, the slab effective elastic modulus and the weak layer specific fracture, overall increased as well. However, the changes with time differed, suggesting that the critical cut length cannot be assessed by simply monitoring a single mechanical property such as slab load, slab modulus or weak layer specific fracture energy. Instead, crack propagation propensity is the result of a complex interplay between the mechanical properties of the slab and the weak layer. We then compared our field observations to newly developed metrics of snow instability related to either failure initiation or crack propagation propensity. The metrics were either derived from the SMP signal or calculated from simulated snow stratigraphy (SNOWPACK). They partially reproduced the observed temporal evolution of critical cut length and instability test scores. Whereas our unique dataset of quantitative measures of snow instability provides new insights into the complex slab-weak layer interaction, it also ... |
format |
Article in Journal/Newspaper |
author |
Schweizer, Jürg id_orcid:0 000-0001-5076-2968 Reuter, Benjamin van Herwijnen, Alec Richter, Bettina Gaume, Johan id_orcid:0 000-0001-8931-752X |
spellingShingle |
Schweizer, Jürg id_orcid:0 000-0001-5076-2968 Reuter, Benjamin van Herwijnen, Alec Richter, Bettina Gaume, Johan id_orcid:0 000-0001-8931-752X Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties |
author_facet |
Schweizer, Jürg id_orcid:0 000-0001-5076-2968 Reuter, Benjamin van Herwijnen, Alec Richter, Bettina Gaume, Johan id_orcid:0 000-0001-8931-752X |
author_sort |
Schweizer, Jürg |
title |
Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties |
title_short |
Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties |
title_full |
Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties |
title_fullStr |
Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties |
title_full_unstemmed |
Temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties |
title_sort |
temporal evolution of crack propagation propensity in snow in relation to slab and weak layer properties |
publisher |
Copernicus |
publishDate |
2016 |
url |
https://hdl.handle.net/20.500.11850/619925 https://doi.org/10.3929/ethz-b-000619925 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, 10 (6) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-10-2637-2016 http://hdl.handle.net/20.500.11850/619925 doi:10.3929/ethz-b-000619925 |
op_rights |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 Unported |
op_doi |
https://doi.org/20.500.11850/61992510.3929/ethz-b-00061992510.5194/tc-10-2637-2016 |
_version_ |
1772820446111072256 |