For the winter 2015-2016 Wyssen Norge AS has been involved in two projects for local avalanche forecasting as a sub-contractor for the company Skred AS. The projects are located in Sørfjorden, Nordland and in Romarheimsdalen, Hordaland.
Local avalanche forecasting
Avalanche forecasting for specific slopes is different from forecasting for larger regions as in public avalanche forecasting services. The 5 step European Avalanche Danger Scale is describing the general conditions in an area of minimum 10km2, and is therefore not directly applicable for this kind of operation. Instead, a 3-step risk scale is used, that describes the probability of an avalanche hitting the object. If the risk is considered too high, different mitigation are carried out. This could include minimizing presence in exposed areas, evacuation or preventive release of avalanches. The forecast also contains an analysis of the current conditions and a description of the avalanche problem(s).
If there is a high level of uncertainty in the forecast, the frequency of the forecast is increased to every 12th or 6th hour. The forecast is based on regularly field observations, automatic weather stations, an advanced remote controlled webcam, information from the Norwegian database for avalanche observations (RegObs), and weather forecasts.
Platform for local avalanche forecasting
When providing services for local avalanche forecasting, good procedures, highly qualified personnel, relevant and accurate data and good documentation is necessary. Therefore, the companies Wyssen Norway, Skred AS and AlpSolut has created a platform to ensure that all procedures are followed every day and that all data and decisions is quality checked and documented.
The platform is based on the ISO 31 000 standard for risk management. The workflow is taking the user through the following stages:
- Observations (weather, snow cover, avalanches etc.)
- Nowcast (likelihood and size in the forecast period, uncertainty, avalanche problems, week layers etc.)
- Verification (compare yesterday’s forecast with what actually happened)
- Weather forecast
- Forecast (likelihood and size in the forecast period, uncertainty, avalanche problems, week layers etc.)
- Summary (analysis of current conditions, validity, risk level)
- Suggestion of necessary mitigation measures
- Quality check by second person and publish forecast
This platform is under continually development and there will be many improvements and new features before next winter.
SmiSto Hydro Power plant
The hydro power plant being built in Norland is the biggest new hydropower project in Norway for the past 11 years. During the construction, several areas are exposed to snow avalanches. To reduce the risk of working in these areas during the wintertime and to avoid any unnecessary closures, Skred AS with Wyssen Norge as a sub-contractor, was hired to provide a daily avalanche forecast every morning before 9am. The service has helped the client to have the required progress and at the same time be able to ensure the safety of the people working on the site.
Romarheimsdalen construction site at Highway E39
In the spring 2015, a big glide avalanche released from the mountain Setrefjellet in Hordaland buried 2 cars on the E39 highway, which is one of the busiest and most important highways in the region. The Norwegian Public Road Administration immediately started to plan protection measures, and in November 2015, the construction of an 11-meter-high protection dam was started. The dam is being built on the upslope side of the road and the construction site is therefore very exposed even for medium sized avalanches.
To reduce the risk of working on the site during the wintertime and to avoid any unnecessary closures, Skred AS, with Wyssen Norge as a sub-contractor, was hired to provide a daily avalanche forecast. The forecast is being published before 4PM and is valid from 7AM the following day. The service has helped the client to have the required progress and at the same time be able to ensure the safety of the people working on the site.