The September 2002 Kolka Glacier Catastrophe in North Ossetia, Russian Federation: Evidence and Analysis

Kotlyakov, V. M.; Rototaeva, O.; Nosenko, G.

doi:10.1659/0276-4741(2004)024[0078:tskgci]2.0.co;2

Cited by 61 publications

(56 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…2.5 km 2 as reconstructed from the satellite images is in correspondence with earlier measurements by Rototaev et al (1983) or Kotlyakov et al (2004). The area affected by erosion amounts to 2.35 km 2 with a zone of 1.2 km 2 showing erosion of several tens of meters deep.…”

Section: Observationssupporting

confidence: 91%

“…In addition to the hot springs around the Maili glacier tongue, indications of surfacing (possibly warm) water in the north-facing wall between Dzhimarai-khokh and Maili glacier were observed in spring 2003. In the slope failure zone, no indications of geothermal activity were recorded, neither during the 9-year monitoring period in the 1970ies (Kotlyakov et al, 2004) nor during summer 2003. Clear and unambiguous evidence from field observations at the site on the potential existence of hot springs and gas liberation in the slope failure zone is therefore missing presently.…”

Section: Assessment and Interpretationmentioning

confidence: 95%

“…Repeated ice and rock fall activity caused asymetric loading on the glacier and debris accumulation between mountain wall and glacier in a ramp-like form. It should also be noted that the summer 2002 in the northern Caucasus was characterized by high precipitation and melting rates of 1.5 to 2 times higher than average (Kotlyakov et al, 2004). This probably contributed to water saturated conditions at the glacial sediment bed and sub/englacial high water pressures.…”

Section: Observationsmentioning

confidence: 99%

“…The overall failure volume is thus between 18.5 and 27×10 6 m 3 , a value considerably higher than initial estimates suggested (less than ca. 10×10 6 m 3 of ice/rock; Kotlyakov et al, 2004;Haeberli et al, 2005). The mass might, however, have partially failed already during days and weeks before the main event of 20 September 2002 (cf.…”

Section: Observationsmentioning

confidence: 99%

“…It has been argued whether geothermal activity influenced the Dzhimarai-khokh slope instability (Kotlyakov et al, 2004). The dust cloud visible on the QuickBird satellite image (Fig.…”

Section: Assessment and Interpretationmentioning

confidence: 99%

See 4 more Smart Citations

The 2002 rock/ice avalanche at Kolka/Karmadon, Russian Caucasus: assessment of extraordinary avalanche formation and mobility, and application of QuickBird satellite imagery

Huggel

Zgraggen-Oswald

Haeberli

et al. 2005

Nat. Hazards Earth Syst. Sci.

255

181

View full text Add to dashboard Cite

Abstract.A massive rock/ice avalanche of about 100×10 6 m 3 volume took place on the northern slope of the Kazbek massif, North Ossetia, Russian Caucasus, on 20 September 2002. The avalanche started as a slope failure, that almost completely entrained Kolka glacier, traveled down the Genaldon valley for 20 km, was stopped at the entrance of the Karmadon gorge, and was finally succeeded by a distal mudflow which continued for another 15 km. The event caused the death of ca. 140 people and massive destruction. Several aspects of the event are extraordinary, i.e. the large ice volume involved, the extreme initial acceleration, the high flow velocity, the long travel distance and particularly the erosion of a valley-type glacier, a process not known so far. The analysis of these aspects is essential for process understanding and worldwide glacial hazard assessments. This study is therefore concerned with the analysis of processes and the evaluation of the most likely interpretations. The analysis is based on QuickBird satellite images, field observations, and ice-, flow-and thermomechanical considerations. QuickBird is currently the best available satellite sensor in terms of ground resolution (0.6 m) and opens new perspectives for assessment of natural hazards. Evaluation of the potential of QuickBird images for assessment of high-mountain hazards shows the feasibility for detailed avalanche mapping and analysis of flow dynamics, far beyond the capabilities of conventional satellite remote sensing. It is shown that the avalanche was characterized by two different flows. The first one was comparable to a hyperconcentrated flow and was immediately followed by a flow with a much lower concentration of water involving masCorrespondence to: C. Huggel ( chuggel@geo.unizh.ch) sive volumes of ice. The high mobility of the avalanche is likely related to fluidization effects at the base of the moving ice/debris mass with high pore pressures and a continuous supply of water due to frictional melting of ice. The paper concludes with implications of the Kolka/Karmadon event for worldwide glacial hazard assessments. It is emphasized that situations with large glacierized high-mountain walls with potentially unstable glaciers within impact distance need special attention and monitoring efforts.

show abstract

Section: Observationssupporting

confidence: 91%

Section: Assessment and Interpretationmentioning

confidence: 95%

Section: Observationsmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

“…It has been argued whether geothermal activity influenced the Dzhimarai-khokh slope instability (Kotlyakov et al, 2004). The dust cloud visible on the QuickBird satellite image (Fig.…”

Section: Assessment and Interpretationmentioning

confidence: 99%

See 3 more Smart Citations

The 2002 rock/ice avalanche at Kolka/Karmadon, Russian Caucasus: assessment of extraordinary avalanche formation and mobility, and application of QuickBird satellite imagery

Huggel

Zgraggen-Oswald

Haeberli

et al. 2005

Nat. Hazards Earth Syst. Sci.

255

181

View full text Add to dashboard Cite

show abstract

A two‐phase mechanical model for rock‐ice avalanches

2014

View full text Add to dashboard Cite

Rock‐ice avalanche events are among the most hazardous natural disasters in the last century. In contrast to rock avalanches, the solid phase (ice) can transform to fluid during the course of the rock‐ice avalanche and fundamentally alter mechanical processes. A real two‐phase debris flow model could better address the dynamic interaction of solid (rock and ice) and fluid (water, snow, slurry, and fine particles) than presently used single‐phase Voellmy‐ or Coulomb‐type models. We present a two‐phase model capable of performing dynamic strength weakening due to internal fluidization and basal lubrication and internal mass and momentum exchanges between the phases. Effective basal and internal friction angles are variable and correspond to evolving effective solid volume fraction, friction factors, volume fraction of the ice, true friction coefficients, and lubrication and fluidization factors. Benchmark numerical simulations demonstrate that the two‐phase model can explain dynamically changing frictional properties of rock‐ice avalanches that occur internally and along the flow path. The interphase mass and momentum exchanges are capable of demonstrating the mechanics of frontal surge head and multiple other surges in the debris body. This is an observed phenomenon in a real two‐phase debris flow, but newly simulated here by applying the two‐phase mass flow model. Mass and momentum exchanges between the phases and the associated internal and basal strength weakening control the exceptional long runout distances, provide a more realistic simulation especially during the critical initial and propagation stages of avalanche, and explain the exceptionally high and dynamically changing mobility of rock‐ice avalanches.

show abstract

Unraveling driving factors for large rock–ice avalanche mobility

Schneider

Huggel

Haeberli

et al. 2011

Earth Surf Processes Landf

145

126

View full text Add to dashboard Cite

Large rock-ice avalanches have attracted attention from scientists for decades and some of these events have caused high numbers of fatalities. A relation between rock slope instabilities in cold high mountain areas and climate change is currently becoming more evident and questions about possible consequences and hazard scenarios in densely populated high mountain regions leading beyond historical precedence are rising. To improve hazard assessment of potential rock-ice avalanches, their mobility is a critical factor. This contribution is an attempt to unravel driving factors for the mobility of large rock-ice avalanches by synthesizing results from physical laboratory experiments and empirical data from 64 rock-ice avalanches with volumes >1x10 6 m 3 from glacierized high mountain regions around the world. The influence of avalanche volume, water and ice content, low-friction surfaces, and topography on the apparent coefficient of friction (as a measure of mobility) is assessed. In laboratory experiments granular ice in the moving mass was found to reduce bulk friction up to 20% while water led to a reduction around 50% for completely saturated material compared with dry flows. Evidence for the effects of water as a key driving factor to enhance mobility was also found in the empirical data, while the influence of the ice content could not be confirmed to be of much relevance in nature. Besides liquefaction, it was confirmed that mobility increases with volumes and that frictional surface characteristics such as flow paths over glaciers are also dominant variables determining mass movement mobility. Effects of the topography along the flow path as well as channeling are assumed to be other critical factors. The results provide an empirical basis to roughly account for different path and flow characteristics of large rock-ice avalanches and to find appropriate ranges for friction parameters for scenario modeling and hazard assessments.

show abstract

The September 2002 Kolka Glacier Catastrophe in North Ossetia, Russian Federation: Evidence and Analysis

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 61 publications

References 1 publication

The 2002 rock/ice avalanche at Kolka/Karmadon, Russian Caucasus: assessment of extraordinary avalanche formation and mobility, and application of QuickBird satellite imagery

The 2002 rock/ice avalanche at Kolka/Karmadon, Russian Caucasus: assessment of extraordinary avalanche formation and mobility, and application of QuickBird satellite imagery

A two‐phase mechanical model for rock‐ice avalanches

Unraveling driving factors for large rock–ice avalanche mobility

Contact Info

Product

Resources

About