New Perspective on Computer-Aided Avalanche Forecasting: Scale and Scale Issues

This paper discusses the problems related to scale in avalanche forecasting models. The term 'scale' refers to a characteristic length or time of a process, observation or model. Following the ideas of Bloschl and Sivapalan (1995), it is shown that the scale characteristics of these three entities can be quite different depending on their individual properties. If these scales do not completely agree with each other, the information transfer between them involves interor extrapolation. This adjustment process between different scales is referred to as 'scaling' and the problems associated with it are scale issues. Ignoring these issues can have significant effects on the quality of the model prediction. The analysis of currently used avalanche forecasting methods and computer models reveals four main problems in this field: (a) the inability of weather monitoring networks to capture small scale phenomena such as snowdrift or surface hoar formation; (b) the insufficient spatiai resolution of snow profile measurements with regard to their natural variability; (c) the poor resolution of stability measurements; and (d) the contradictions between input and output scales in avalanche forecasting models. Preliminary thoughts for the solution of these scale problems are presented in this paper.

[1]  Karl W. Birkeland,et al.  The spatial variability of snow resistance on potential avalanche slopes , 1995, Journal of Glaciology.

[2]  Jeremy Fairbank,et al.  Historical Perspective , 1987, Do We Really Understand Quantum Mechanics?.

[3]  Günter Blöschl,et al.  Scaling issues in snow hydrology , 1999 .

[4]  J. Schweizer.  Review of dry snow slab avalanche release , 1999 .

[5]  P. Föhn.  Simulation of surface-hoar layers for snow-cover models , 2001, Annals of Glaciology.

[6]  J. Jamieson,et al.  Avalanche prediction for persistent snow slabs , 1995 .

[7]  P. M. Fôhn.  Snowcover Stability Tests and the Areal Variability of Snow Strength , 1988 .

[8]  I. Orlanski.  A rational subdivision of scales for atmospheric processes , 1975 .

[9]  Murugesu Sivapalan,et al.  Scale issues in hydrological modelling: A review , 1995 .

[10]  E. Martin,et al.  A computer-based system simulating snowpack structures as a tool for regional avalanche forecasting , 1999, Journal of Glaciology.

[11]  Martin Schweizer,et al.  Integrating Neural Networks and Rule Based Systems to build anAvalanche Forecasting System. , 1994 .

[12]  David M. McClung,et al.  Use of Expert Knowledge in Avalanche Forecasting . , 1995 .

[13]  D. Mcclung,et al.  The Avalanche Handbook , 1993 .

[14]  Jürg Schweizer,et al.  Avalanche forecasting : an expert system approach , 1996 .

[15]  David M. McClung.  Predictions in avalanche forecasting , 2000, Annals of Glaciology.

[16]  D. Mcclung,et al.  Numerical avalanche prediction: Kootenay Pass, British Columbia, Canada , 1994, Journal of Glaciology.

[17]  Michael Lehning,et al.  snowpack model calculations for avalanche warning based upon a new network of weather and snow stations , 1999 .