Future Risk of Geohazards in Norway

Snow avalanche is a rare and irreproducible event, which makes the quantitative understanding of this phenomenon quite difficult and narrow. Avalanche hazard has been described by (Bakkehoi, 1987) as a product of the probability for an avalanche to occur, the size of the avalanche and the consequences. Furthermore, a detailed analysis of snow avalanche hazard by using this method can be found in (Bakkehoi, 1987). We cannot stop the occurrence of snow avalanches but as a risk analyst, our target is to reduce the hazards of snow avalanche to an acceptable level. So far, acceptance level of snow avalanche risk has not been established yet. In recent years, research and studies are seen on this issue. Hazard mapping and zoning are usually adapted for this purpose. Hazard mapping implicates determining the probable extent of snow avalanche. Tools like air photographs, analysis of past records, studies of snow and climatic data and so on are generally used. Land-use planning plays an important role in avalanche risk management and mapping the possible hazards. But there is a lack of knowledge in determining the role of snow avalanches in the coupled geomorphic process chain.

2.2.4 Future Risk of Geohazards in Norway

Various incidents of snow avalanche during every winter and a recent landslide hazard near Voss indicate that Norway is at risk of geohazards. According to (Berglund, 2016), the slide was massive with more boulders, trees and rocks sliding onto the E16 Highway and out of the fjord. It caused inconvenience in carrying out emergency operations too. With these kinds of landslides and rock falls or snow avalanches, there is a risk of losing lives, while on the other hand; they block the roads causing impacts on the traffic. Consequently, the risk increases due to such effect in traffic as the exposure groups and vulnerability increases. Temperature and precipitation have a great influence on geohazards in Norway (discussed in Section 2.2).

Norway’s land profiles being lengthened over latitude, these elements vary consequently,

increasing mostly during winter seasons. (Jaedicke et al., 2008) points out to an increase in the likelihood of situations leading to geohazardous events due to the regional climatic changes. It foretells about rising frequency and strength of extreme weather events in Norway in the next 50 years. In this issue, a 4 year (2005-2008) project called GeoExtreme was run in Norway, which focused on investigating the coupling between meteorological factors and landslides and avalanches, extrapolating this into the near future with a changing climate and estimating the socio-economic implications. (ICG, 2006; Jaedicke et al., 2008) explain in detail about this project.

Along with the increasing risks of rockslides and tsunami related floods, there is also a great spatial variability in snow depth in Norway due to the presence of coastal, mountain and inland climates (Dyrrdal et al., 2011). Central and mountainous regions of Norway comprise of largest depth of snow, while the coastal regions have less. Increasing trends of precipitation and wind speed in mountainous and central regions as seen in (Dyrrdal et al., 2011) refer to increasing frequency and risks of snow avalanches in the nearest future. As many as ten major snow avalanche disasters can be expected over the hundred years leading to a plentiful loss of life if necessary steps are not taken (NGI, s.a.). However, some uncertainties have to be faced during this analysis of trends of climatic conditions and snowfall. Uncertainties arise due to complex land topography of Norway. Despite the researches and projects been carried out on geohazards in Norway; there is a need to focus on formulating plans and strategies on regional basis. This will be helpful for creating the spatial variation of climatic conditions at various parts of the country. It also adds effectiveness in mitigative plans. There is also a need of more scientific research on changing geohazardous conditions by evaluating the past hazards, their occurring patterns and potential triggers. This helps to prevent socio-economic risks in the nearest future as well as to improve mitigation strategies. In addition, prediction of possible geohazards with the changing climatic conditions can also be useful in reducing the future risks. Increasing public awareness of geohazards and establishing a geohazard-focused program is necessary (Solheim et al., 2005). Furthermore, it adds that there is a need to improve the basic understanding and our ability to deal with the risks associated with them.

Mitigation of hazards is an essential task for minimizing the probable risks and consequences. These measures can vary for any specific situations and the prevailing geohazards. Success of such measures relies on reliability of the implemented measures. But in some of the cases, existing knowledge gap on proper understanding of hazardous situations and the relevant uncertainties associated with them can cause difficulty in quantifying the efficiency of mitigating measures. Hence, it is necessary to carry out an assessment regarding the effectiveness of mitigation measures for that particular scenario. In addition to this, one should ensure that the applied mitigation measures fulfill a particular level of safety, quality and sustainability. It is suggested to start projects focused on proper investigation and monitoring of unstable rock slopes, snow avalanche and other hazard prone areas. An observation on past failure activities should also be carried out for estimating future occurrence and risks of geohazards. Similarly, early warning systems for any predictable events should be enhanced in the case of Norway so that people can be alert beforehand.

Evacuation systems and escape routes should be prioritized for safety against the future hazards. Avoidance of settlement on hazard prone areas like quick clay zones and under unstable slopes, can to some extent be useful in reducing vulnerability, and subsequently, the future risk.