First approaches towards modelling glacial hazards in the Mount Cook region of New Zealand's Southern Alps

Abstract

Abstract. Flood and mass movements originating from glacial environments are particularly devastating in populated mountain regions of the world, but in the remote Mount Cook region of New Zealand's Southern Alps minimal attention has been given to these processes. Glacial environments are characterized by high mass turnover and combined with changing climatic conditions, potential problems and process interactions can evolve rapidly. Remote sensing based terrain mapping, geographic information systems and flow path modelling are integrated here to explore the extent of ice avalanche, debris flow and lake flood hazard potential in the Mount Cook region. Numerous proglacial lakes have formed during recent decades, but well vegetated, low gradient outlet areas suggest catastrophic dam failure and flooding is unlikely. However, potential impacts from incoming mass movements of ice, debris or rock could lead to dam overtopping, particularly where lakes are forming directly beneath steep slopes. Physically based numerical modeling with RAMMS was introduced for local scale analyses of rock avalanche events, and was shown to be a useful tool for establishing accurate flow path dynamics and estimating potential event magnitudes. Potential debris flows originating from steep moraine and talus slopes can reach road and built infrastructure when worst-case runout distances are considered, while potential effects from ice avalanches are limited to walking tracks and alpine huts located in close proximity to initiation zones of steep ice. Further local scale studies of these processes are required, leading towards a full hazard assessment, and changing glacial conditions over coming decades will necessitate ongoing monitoring and reassessment of initiation zones and potential impacts.

Glacial lake outburst flood risk in Himachal Pradesh, India: an integrative and anticipatory approach considering current and future threats

“…For moraine-dammed lakes, further parameters that may be integrated within a more complete large-scale assessment of dam stability and current GLOF hazard include dam geometry and freeboard height (Huggel et al 2004), the steepness of the lake front area (Fujita et al 2013), growth of the lake and associated glacier retreat (Bolch et al 2008), vegetation coverage in the dam area (Allen et al 2009), and permafrost conditions (Bolch et al 2011). However, some of these factors become highly uncertain, or, for dam characteristics, impossible to establish for the modelled future lakes.…”

Identification of potentially dangerous glacial lakes in the northern Tien Shan

“…The model is a modified D8 flow direction algorithm and calculates the likelihood that a raster cell will be affected by such a mass movement. Similar methods to model rock and ice avalanches were applied by Allen et al (2009) and Salzmann et al (2004). Unfortunately, no detailed ground information is available for the study area.…”

Modeling debris-flow runout patterns on two alpine fans with different dynamic simulation models

“…Debris-flow parameters from other studies (Scheidl et al, 2013;McDougall et al, 2006;Hungr et al, 2002;Hungr, 2008b;Bartelt et al, 2013b;Jakob et al, 2000), are given as brown squares. Rock avalanches are illustrated as green circles and ice-rock avalanches are denoted by blue diamonds (Pirulli et al, 2004;Evans, 1996, 2004;Hungr and McDougall, 2009;Hungr, 2008b;Evans et al, 2007;Allen et al, 2009;Sosio et al, 2008;Lipovsky et al, 2008;Schneider et al, 2010). Suggested parameter ranges for small (< 25 000 m 3 ) and large (> 25 000 m 3 ) snow avalanches are given in two different shaded areas (Bartelt et al, 2013a).…”