RAMMS::Extended
The RAMMS::Extended model is a cutting-edge tool designed to simulate mixed flowing and powder snow avalanches in complex, three-dimensional terrain. Expanding on the capabilities of RAMMS::Avalanche, this model introduces critical enhancements including snow entrainment, powder cloud formation, and temperature-dependent flow behavior. These advanced features enable more accurate predictions of avalanche dynamics, interactions with terrain and vegetation, and the associated impact pressures on infrastructure.
In RAMMS::Extended a snow avalanche consists of six physical components. Three of these represent the snow avalanche itself: the
avalanche core, the powder cloud, and the pre-front or splashing front. The dynamics of these three components are governed by depth-averaged mass, momentum, and energy balances. The remaining three components represent terrain and environmental boundary conditions: the snowcover, the surrounding air, and the mountain forest.
Theory
The RAMMS::Extended model describes avalanches as a combination of two primary flow layers: a dense core of snow clumps and a powder cloud of airborne ice-dust. The core is modeled as a granular flow driven by gravity and shear forces, where snow granules behave like a flowing mixture of solid particles. The powder cloud forms when fine ice-dust particles are suspended in turbulent air, driven by momentum transferred from the core.
The two layers move together but have different densities and speeds, created by natural segregation: larger snow granules settle rapidly, while smaller ice-dust particles remain suspended. This dual-layer flow captures the complex behavior of mixed avalanches, from the dense, ground-hugging core to the far-reaching, high-speed powder cloud.
Additionally, RAMMS::Extended incorporates snow entrainment—the process of adding snow from the ground into the moving avalanche—affecting mass, energy, and momentum. The model also accounts for temperature variations and meltwater formation within the core, enabling transitions between dry and wet flow regimes. Forest interactions are included, simulating how trees reduce avalanche energy, intercept snow, and may break under avalanche forces.
Together, these elements provide a detailed and realistic representation of avalanche behavior, crucial for hazard assessments and engineering applications.
Random Energy
Simulates internal energy fluctuations in the avalanche core, driving dispersive expansion and transitions between dense flow and turbulent powder regimes.
Coming more soon, or ask Rocky.
Entrainment
Captures the dynamic incorporation of snow from the slope into the avalanche mass, aligning simulations with real-world mass balances and improving predictive accuracy.
Coming more soon, or ask Rocky.
Temperature
Integrates snow temperature and meltwater dynamics into the avalanche simulation, enabling realistic transitions between dry and wet flow regimes and accounting for thermal-structural interactions.
Coming more soon, or ask Rocky.
Powder Cloud
Models the formation, propagation, and air-blast impact of ice-dust clouds generated from the avalanche core, crucial for hazard assessments near structures and forests.
Coming more soon, or ask Rocky.
Downloads
RAMMS::Extended
Publications
EXTENDED Publication List
Meyrat G., Munch J., Cicoira A., McArdell B., Müller C.R., Frey H., Bartelt P. (2024) Simulating glacier lake outburst floods (GLOFs) with a two-phase/layer debris flow model considering fluid-solid flow transitions. Landslides. 21(479), 497. doi:10.1007/s10346-023-02157-w Institutional Repository DORA
Zhuang Y., Bartelt P., Xing A., Bilal M. (2024) Rock avalanche-induced air blasts: implications for landslide risk assessments. Geomorphology. 452, 109111 (11 pp.). doi:10.1016/j.geomorph.2024.109111 Institutional Repository DORA
Dasser G., Munch J., Bühler Y., Bartelt P., Manconi A. (2023) Applied space-borne remote sensing to identify mass movements and the exemplary modelling of potentially catastrophic failures in the Bhagirathi Area, India. In T. P. Kersten & N. Tilly (Eds.), Publikationen der Deutschen Gesellschaft für Photogrammetrie, Fernerkundung und Geoinformation e.V.: Vol. 31. 43. wissenschaftlich-technische Jahrestagung der DGPF in München. Jahrestagung der DGPF. Photogrammetrie, Fernerkundung, Geoinformation. Stuttgart: Deutsche Gesellschaft für Photogrammetrie, Fernerkundung und Geoinformation (DGPF). 276-287. Institutional Repository DORA
Miller A.D., Redpath T.A.N., Sirguey P., Cox S.C., Bartelt P., Bogie D., … Bühler Y. (2023) Unprecedented winter rainfall initiates large snow avalanche and mass movement cycle in New Zealand’s Southern Alps/Kā Tiritiri o te Moana. Geophys. Res. Lett. 50(8), e2022GL102105 (11 pp.). doi:10.1029/2022GL102105 Institutional Repository DORA
Gorynina O., Bartelt P. (2023) Powder snow avalanche impact on hanging cables. Int. J. Impact Eng. 173, 104422 (11 pp.). doi:10.1016/j.ijimpeng.2022.104422 Institutional Repository DORA
Glaus J., Wikstrom Jones K., Bühler Y., Christen M., Ruttner-Jansen P., Gaume J., Bartelt P. (2023) RAMMS::EXTENDED – Sensitivity analysis of numerical fluidized powder avalanche simulation in three-dimensional terrain. In International snow science workshop proceedings 2023. Bozeman: Montana State University Library. 795-802. Institutional Repository DORA
Munch J., Bartelt P., Christen M. (2023) Multi-component avalanches for rock- and ice-falls to potential debris flow transition modelling. In M. Pirulli, A. Leonardi, & F. Vagnon (Eds.), E3S web of conferences: Vol. 415. 8th international conference on debris flow hazard mitigation (DFHM8). Les Ulis Cedex A: EDP Sciences. 01017 (4 pp.). doi:10.1051/e3sconf/202341501017 Institutional Repository DORA
Zhuang Y., Piazza N., Xing A., Christen M., Bebi P., Bottero A., … Bartelt P. (2023) Tree blow-down by snow avalanche air-blasts: dynamic magnification effects and turbulence. Geophys. Res. Lett. 50(21), e2023GL105334 (12 pp.). doi:10.1029/2023GL105334 Institutional Repository DORA
Ivanova, K.; Caviezel, A.; Bühler, Y.; Bartelt, P., 2022: Numerical modelling of turbulent geophysical flows using a hyperbolic shear shallow water model: application to powder snow avalanches. Computers and Fluids, 233: 105211 (9 pp.). doi: 10.1016/j.compfluid.2021.105211
Caviezel, A.; Margreth, S.; Ivanova, K.; Sovilla, B.; Bartelt, P., 2021: Powder snow impact of tall vibrating structures. In: Papadrakakis, M.; Fragiadakis, M. (eds), 2021: Compdyn 2021 proceedings. COMPDYN 2021. 8th ECCOMAS thematic conference on computational methods in structural dynamics and earthquake engineering, Athens, Greece. 19112 (13 pp.).
Frigo, B.; Bartelt, P.; Chiaia, B.; Chiambretti, I.; Maggioni, M., 2021: A reverse dynamical investigation of the catastrophic wood-snow avalanche of 18 January 2017 at Rigopiano, Gran Sasso National Park, Italy. International Journal of Disaster Risk Science, 12: 40-55. doi: 10.1007/s13753-020-00306-6
Miller, A.; Sirguey, P.; Morris, S.; Bartelt, P.; Cullen, N.; Buhler, Y., 2021: Avalanche modelling on the Milfoard Road. New Zealand Avalanche Dispatch, 43-47.
Brožová, N.; Fischer, J.; Bühler, Y.; Bartelt, P.; Bebi, P., 2020: Determining forest parameters for avalanche simulation using remote sensing data. Cold Regions Science and Technology, 172: 102976 (11 pp.). doi: 10.1016/j.coldregions.2019.102976
Bartelt, P.; Buser, O.; Christen, M.; Caviezel, A., 2019: Dynamic magnification factors for snow avalanche impact (with pile-up) on walls and pylons. In: Papadrakakis, M.; Fragiadakis, M. (eds), 2019: COMPDYN 2019. 7th international conference on computational methods in structural dynamics and earthquake engineering. Proceedings. COMPDYN 2019. 7th ECCOMAS thematic conference on computational methods in structural dynamics and earthquake engineering, Crete, Greece. 4376-4385.
Kääb, A.; Leinss, S.; Gilbert, A.; Bühler, Y.; Gascoin, S.; Evans, S.G.; Bartelt, P.; Berthier, E.; Brun, F.; Chao, W.; Farinotti, D.; Gimbert, F.; Guo, W.; Huggel, C.; Kargel, J.S.; Leonard, G.J.; Tian, L.; Treichler, D.; Yao, T., 2018: Massive collapse of two glaciers in western Tibet in 2016 after surge-like instability. Nature Geoscience, 11, 2: 114-120. doi: 10.1038/s41561-017-0039-7
Vera Valero, C.; Wever, N.; Christen, M.; Bartelt, P., 2018: Modeling the influence of snow cover temperature and water content on wet-snow avalanche runout. Natural Hazards and Earth System Science, 18, 3: 869-887. doi: 10.5194/nhess-18-869-2018
Bühler, Y.; Von Rickenbach, D.; Stoffel, A.; Margreth, S.; Stoffel, L.; Christen, M., 2018: Automated snow avalanche release area delineation – validation of existing algorithms and proposition of a new object-based approach for large-scale hazard indication mapping. Natural Hazards and Earth System Science, 18, 12: 3235-3251. doi: 10.5194/nhess-18-3235-2018
Bartelt, P.; Christen, M.; Bühler, Y.; Buser, O., 2018: Thermomechanical modelling of rock avalanches with debris, ice and snow entrainment. In: Cardoso, A.S.; Borges, J.L.; Costa, P.A.; Gomes, A.T.; Marques, J.C.; Vieira, C.S. (eds), 2018: Numerical methods in geotechnical engineering IX. 9th European conference on numerical methods in geotechnical engineering (NUMGE 2018), Porto. 1047-1054.
Wikstrom Jones, K.; Loso, M.G.; Bartelt, P., 2018: Modeled mass and temperature effects of entrained snow on the lubricated flow regime and implications for predicting avalanche runout distance. In: 2018: International snow science workshop proceedings 2018. International snow science workshop, ISSW 2018, Innsbruck. 84-88.
Schmidtner, K.; Bartelt, P.; Fischer, J.; Sailer, R.; Granig, M.; Sampl, P.; Fellin, W.; Stoffel, L.; Christen, M.; Bühler, Y., 2018: Comparsion of powder snow avalanche simulation models (RAMMS and SamosAT) based on reference events in Switzerland. In: 2018: International snow science workshop proceedings 2018. International snow science workshop, ISSW 2018, Innsbruck. 740-745.
Riba Porras, S.; García-Sellés, C.; Bartelt, P.; Stoffel, L., 2018: Analysis of one avalanche zone in the Eastern Pyrenees (Val d’Aran) using historical analysis, snow-climate data and mixed flowing/powder avalanche modelling. In: 2018: International snow science workshop proceedings 2018. International snow science workshop, ISSW 2018, Innsbruck. 561-565.
Frigo, B.; Chiaia, B.; Chiambretti, I.; Bartelt, P.; Maggioni, M.; Freppaz, M., 2018: The January 18th 2017 Rigopiano disaster in Italy – analysis of the avalanche dynamics. In: 2018: International snow science workshop proceedings 2018. International snow science workshop, ISSW 2018, Innsbruck. 6-10.
Bartelt, P.; Christen, M.; Bühler, Y.; Caviezel, A.; Buser, O., 2018: Snow entrainment: avalanche interaction with an erodible substrate. In: 2018: International snow science workshop proceedings 2018. International snow science workshop, ISSW 2018, Innsbruck. 716-720.
Bartelt, P.; Buser, O., 2018: Avalanche dynamics by Newton. Reply to comments on avalanche flow models based on the concept of random kinetic energy. Journal of Glaciology, 64, 243: 165-170. doi: 10.1017/jog.2018.1
Bartelt, P.; Bebi, P.; Feistl, T.; Buser, O.; Caviezel, A., 2018: Dynamic magnification factors for tree blow-down by powder snow avalanche air blasts. Natural Hazards and Earth System Science, 18, 3: 759-764. doi: 10.5194/nhess-18-759-2018
Bartelt, P.; Buser, O., 2016: Reply to “Discussion of “The relation between dilatancy, effective stress and dispersive pressure in granular avalanches” by P. Bartelt and O. Buser (DOI: 10.1007/s11440-016-0463-7)” by Richard Iverson and David L. George (DOI: 10.1007/s11440-016-0502-4). Acta Geotechnica, 11, 6: 1469-1473. doi: 10.1007/s11440-016-0503-3
Bartelt, P.; Buser, O., 2016: The relation between dilatancy, effective stress and dispersive pressure in granular avalanches. Acta Geotechnica, 11, 3: 549-557. doi: 10.1007/s11440-016-0463-7
Dreier, L.; Bühler, Y.; Ginzler, C.; Bartelt, P., 2016: Comparison of simulated powder snow avalanches with photogrammetric measurements. Annals of Glaciology, 57, 71: 371-381. doi: 10.3189/2016AoG71A532
Bartelt, P.; Buser, O.; Vera Valero, C.; Bühler, Y., 2016: Configurational energy and the formation of mixed flowing/powder snow and ice avalanches. Annals of Glaciology, 57, 71: 179-188. doi: 10.3189/2016AoG71A464
Stoffel, L.; Margreth, S.; Schaer, M.; Christen, M.; Bühler, Y.; Bartelt, P., 2016: Powder snow avalanche engineering: new methods to calculate air-blast pressures for hazard mapping. In: Koboltschnig, G. (eds), 2016: 13th congress INTERPRAEVENT 2016. 30 May to 2 June 2016. Lucerne, Switzerland. Conference proceedings “Living with natural risks”. 13th congress INTERPRAEVENT 2016, Lucerne, Switzerland, May 30-June 2, 2016. 416-425.
Feistl, T.; Fischer, A.; Bebi, P.; Bartelt, P., 2016: Evaluation of protection measures against avalanches in forested terrain. In: 2016: International snow science workshop proceedings 2016. International snow science workshop, ISSW 2016, Breckenridge, CO, USA, October 2-7, 2016. 561-568.
Wikstrom Jones, K.; Bartelt, P.; Loso, M., 2016: Modeled mass and temperature effects of released and entrained snow on the lubricated wet flow regime of avalanches at Bird Hill, southcentral Alaska. In: 2016: International snow science workshop proceedings 2016. International snow science workshop, ISSW 2016, Breckenridge, CO, USA, October 2-7, 2016. 501-508.
Vera Valero, C.; Wever, N.; Bartelt, P., 2016: Coupling operational snowcover simulations with avalanche dynamics calculations to assess avalanche danger in high altitude mining operations. In: 2016: International snow science workshop proceedings 2016. International snow science workshop, ISSW 2016, Breckenridge, CO, USA, October 2-7, 2016. 159-164.
Vera Valero, C.; Wever, N.; Bühler, Y.; Stoffel, L.; Margreth, S.; Bartelt, P., 2016: Modelling wet snow avalanche runout to assess road safety at a high-altitude mine in the central Andes. Natural Hazards and Earth System Science, 16, 11: 2303-2323. doi: 10.5194/nhess-16-2303-2016
Bartelt, P.; Vera Valero, C.; Feistl, T.; Christen, M.; Bühler, Y.; Buser, O., 2015: Modelling cohesion in snow avalanche flow. Journal of Glaciology, 61, 229: 837-850. doi: 10.3189/2015JoG14J126
Buser, O.; Bartelt, P., 2015: An energy-based method to calculate streamwise density variations in snow avalanches. Journal of Glaciology, 61, 227: 563-575. doi: 10.3189/2015JoG14J054
Vera Valero, C.; Wikstroem Jones, K.; Bühler, Y.; Bartelt, P., 2015: Release temperature, snow-cover entrainment and the thermal flow regime of snow avalanches. Journal of Glaciology, 61, 225: 173-184. doi: 10.3189/2015JoG14J117
Feistl, T.; Bebi, P.; Christen, M.; Margreth, S.; Diefenbach, L.; Bartelt, P., 2015: Forest damage and snow avalanche flow regime. Natural Hazards and Earth System Science, 15, 6: 1275-1288. doi: 10.5194/nhess-15-1275-2015
Feistl, T.; Bebi, P.; Teich, M.; Bühler, Y.; Christen, M.; Thuro, K.; Bartelt, P., 2014: Observations and modeling of the braking effect of forests on small and medium avalanches. Journal of Glaciology, 60, 219: 124-138. doi: 10.3189/2014JoG13J055
Feistl, T.; Bebi, P.; Dreier, L.; Hanewinkel, M.; Bartelt, P., 2014: Quantification of basal friction for technical and silvicultural glide-snow avalanche mitigation measures. Natural Hazards and Earth System Science, 14, 11: 2921-2931. doi: 10.5194/nhess-14-2921-2014
Teich, M.; Fischer, J.-T.; Feistl, T.; Bebi, P.; Christen, M.; Grêt-Regamey, A., 2014: Computational snow avalanche simulation in forested terrain. Natural Hazards and Earth System Science, 14, 8: 2233-2248. doi: 10.5194/nhess-14-2233-2014
