case study on snow avalanches - davos frauentobel,...
TRANSCRIPT
![Page 1: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/1.jpg)
Irasmos Symposium „A Merge of Theory and Practice“ May 15-16, 2008
Case study on snow avalanches -Davos Frauentobel, Switzerland
Michael Bründl
WSL – Swiss Federal Institute for Snowand Avalanche Research SLF
![Page 2: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/2.jpg)
Outline
1. From a local problem of safety services to riskassessment.
2. From risk assessment to planning and optimisation of countermeasures.
3. Realisation of the safety concept in practice.
4. Conclusions.
![Page 3: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/3.jpg)
From a local problemof safety services
to risk assessment.
![Page 4: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/4.jpg)
Investigation area Davos FrauentobelCongresscentre
• within last 400 years 13 fatalities
• 17 avalanche events between1951 and 1999, 1 fatality(1968)
• road is connection to ski resort.
![Page 5: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/5.jpg)
Davos Frauentobel
![Page 6: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/6.jpg)
From risk assessment to planning and optimisation of
countermeasures.
![Page 7: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/7.jpg)
Release areas and slope angle
305304
307308
![Page 8: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/8.jpg)
30-year Scenario
100-year Scenario 300-year Scenario
Identification of realisticscenarios, estimation of impact.
Two components:- event analysis- impact analysis
Hazard analysis – intensity maps without measures
![Page 9: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/9.jpg)
Exposure analysis: exposed objects
24 residential houses1 church1 school2 hotels1 railway station2 public buildings15 stables with livestock3 garages
roadrailway
Number persons: 185Damage potential: 51 million CHF
33 million Euro
![Page 10: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/10.jpg)
Consequence analysis
,( ) (1 ( ))i j Sp buiL ep p r op Np V λ= ⋅ − ⋅ ⋅ ⋅
Calculation of loss(e.g. persons in buildings):
pSp = spatial variabilityr(op) = object protectionbuildings
Np = number of personsVbui = vulnerability of
buildingsl = mortality of persons
![Page 11: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/11.jpg)
Presentation initial risk in FN-DiagrammeEx
ceed
ance
prob
abili
typ ≥
D
Damage D in CHF
![Page 12: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/12.jpg)
Identification of certain persons, which areespecially endangered.
ri (b11) = 1.94 x 10-3
p(pr) = 0.8, i.e. in 80% of the time the person is present in the house.
protection goal ri(max) ≤ 1 x 10-5 is violated.
Building No. 11
Calculation of individual risk
![Page 13: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/13.jpg)
Protection goals, example Switzerland
Category Individual risk (CH) Societal risk(VSL, CH)x 106 CHF
Example
high degree of self control(category 1-2, PLANAT-Strategy)
10-2 ≤ ri ≤ 1x 10-5 1 - 5
5 – 20
alpine climbing, working risks
car driving on mountain roads
low degree of self control(category 3-4, PLANAT-Strategy)
ri ≤ 1x 10-5 train riding,living in blue orred hazardzones.
![Page 14: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/14.jpg)
• improvement of organisational measures(evacuation and closure)
• artificial avalanche release
• defence structures of several release areas(here 304, 307, 308)
• combination of these measures
Considered measures
![Page 15: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/15.jpg)
30-year Scenario
100-year Scenario 300-year Scenario
Hazard analysis – intensity maps after therealisation of measures
- Hazard analysis assumingrealisation of measures.
- Calculation or estimation of intensity maps.e.g. defence structures in the release zone.
![Page 16: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/16.jpg)
Presentation of societal riskafter countermeasures
Exce
edan
cepr
obab
ility
p ≥
D
Damage D in CHF
Evacuation+closure+artifical release
![Page 17: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/17.jpg)
Risk-Cost Curve Davos Frauentobel
without weighting of damage (risk aversion)5 mio CHF/averted fatality
Evacuation+closure road andrailway + artificial release
CE = 1
![Page 18: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/18.jpg)
Risk-Cost Curve Davos Frauentobel
Evacuation+closure road andrailway + artificial release
without weighting of damage (risk aversion)10 mio CHF/averted fatality
![Page 19: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/19.jpg)
Communication to the affected population
• Results were presented and discussed with the local safetyservices
• Presentation of the results to the affected, discussion aboutproblems, constraints, etc.
• Information in the local newspaper.
![Page 20: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/20.jpg)
Realisation of thesafety concept in practice.
![Page 21: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/21.jpg)
Realisation of safety concept
Targets for army weapons (mortar)
Closure plan
![Page 22: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/22.jpg)
Artificial release 7 February 2003
Schedule:1. preparation safety service2. information residents3. coordination4. decision5. closure6. safety action7. check of success8. road clearing9. road opening10. information residents
![Page 23: Case study on snow avalanches - Davos Frauentobel, …irasmos.slf.ch/Presentations/michael-bruendl_2.pdf• road is connection to ski resort. Davos Frauentobel. From risk assessment](https://reader033.vdocument.in/reader033/viewer/2022051906/5ff8d9f7dc71f33f4c70b6f5/html5/thumbnails/23.jpg)
• Risk based planning of countermeasures becomes more and more the state-of-the-art in many alpine countries.
• Although there are uncertainties the result of risk analyses provide valuable basis for decisions.
• Information and communication with the affected population is a critical factor for success.
• This case study can be regarded as “best-practice example” of a collaboration between science and practice.
Conclusions