Conceptual model for quantification of snow avalanche return periods

This note is a contribution to the InfraRisk project (Module B) where one of the aims is to suggest an improved standard for hazard mapping. In particular, it is attempted to overcome the deficieney pointed out for *WP Bl Hazard Mapping” stating that today"s hazard maps are inappropriate to assess the risk inside the hazard zone (the maps define only the frequency of an expected event and most often only along a single line). The aim of this study is to establish a conceptual model for quantification of snow avalanche return periods at any given location along the avalanche track. The conceptual model is based on the modified a/B-model presented by Harbitz et al. (2001), which is again based on the original topographical/statistical /B-model (e.g. Bakkehøi et al. 1983; a summary description is also presented by Harbitz 1998).Norges Forskningsråd (NFR

Significance of historical records for avalanche hazard zoning in Norway

In avalanche hazard zoning, it is common practice to investigate the previous avalanche history for the area considered. Historical observations of avalanches serve as an aid in the classification of the terrain, and may also serve as verification of estimates of avalanche runout. Conditions influencing the avalanche occurrences may change significantly over time and it is important to take these changes into account when using historical avalanche observations in hazard ioning today. A number of the most extensive avalanches recorded in Norway, are found during the eigthteenth and nineteenth century. The catastrophes may be linked to weather as well as to socio-econornic conditions, in particular deforestation of mountain slopes. The implications of using or disregarding historical avalanche observation are shown in an example of statistical estimation of avalanche runout

On probability analysis in snow avalanche hazard zoning

The reduced societal acceptance of living in regions exposed to snow avalanches, and the increased economic consequences when houses are located within a hazard zone, highlight the uncertainty concerning avalanche run-out prediction. The limitations of today’s zoning procedures are especially pronounced in potential avalanche terrain where there are few observations of snow avalanches, where old buildings are present in the potential run-out zone, and where the local climate does not favour severe snow accumulation. This paper combines a mechanical probabilistic model for avalanche release with a statistical/topographical model for avalanche run-out distance to obtain the unconditional probability of extreme run-out distance. For the mechanical model, a first-order reliability method (FORM) and Monte Carlo simulations are compared. The interpretation of the statistical/topographical model either as an extreme value model or as a single value model is discussed. Furthermore, both a classical approach where the probability of an avalanche occurring is a constant, and a Bayesian approach with stochastic probability, are compared. Finally, example applications in hazard zoning are presented, with emphasis on how the influence of historical observations, local climate, etc., on run-out distance can be quantified in statistical terms and how a specified certainty level can be found from constructing confidence intervals for, for example, the most likely largest run-out distance during various time intervals

Parameter-sparse modification of Fourier methods to analyse the shape of closed contours with application to otolith outlines

-Elliptical Fourier descriptors (EFDs) have been used extensively in shape analysis of closed contours and have a range of marine applications, such as automatic identification of fish species and discrimination between fish stocks based on EFDs of otolith contours. A recent method (the ‘MIRR’ method) transforms the two-dimensional contour to a one-dimensional function by mirroring (reflecting) the lower half of the contour around a vertical axis at the right end of the contour. MIRR then applies the fast Fourier transform (FFT) to the vertical contour points corresponding to equidistant coordinate values along the horizontal axis. MIRR has the advantage of reducing the number of Fourier coefficients to two coefficients per frequency component compared with four EFDs. However, both Fourier methods require several frequency components to reproduce a pure ellipse properly. This paper shows how the methods can be easily modified so that a virtually perfect reproduction of a pure ellipse is obtained with only one frequency component. In addition, real otolith examples for cod (Gadus morhua) and Greenland halibut (Reinhardtius hippoglossoides) are used to demonstrate that the modified methods give better approximations to the large-scale shape of the original contour with fewer coefficients than the traditional Fourier methods, with negligible additional computing time

A zigzag survey design for continuous transect sampling with guaranteed equal coverage probability

Marine resource surveys in large areas have high cost, and to find an optimal survey design with regard to efficiency and scientific outcome is an important issue. A randomized zigzag design for straight line and curved transects is developed that guarantees equal coverage probability, i.e., each point in the study area has the same probability of being covered by the transect. The basic idea is to fit automatically either the smallest rectangle, or the smallest circular sector enclosing the actual area. Then a recipe for the location of zigzag legs that provide equal coverage probability everywhere in the rectangle or circular sector is outlined, and thereby also at any location within the study area, which simplifies unbiased abundance estimation. The cost of this approach is the unwanted distance to be traveled from the point where a transect leg leaves the study area to the point where the next leg enters. A comparison of a randomized parallel, straight line zigzag, and curved zigzag approach applied to 7 sandeel areas with great variety revealed an average off-effort traveling distance of 28%, 9% and 6%, respectively. Thus, it appears that the developed zigzag design is far more efficient than the parallel design.publishedVersio

EU Programme SAME. Draft proposal for a co-ordinated European full-scale avalanche experiment

The scope of this proposal is to describe the conclusions made in the EU programme SAME (Avalanche Mapping, Model Validation and Warning Systems) for a future co-ordinated European full-scale avalanche experiment. It is not meant to be a completed and final application for financial support in its present stage. A final application will hopefully come into being when the real participants in a potential co-ordinated experiment are singled out.EU kommisjone

EU programme CADZIE. New concepts in avalanche hazard mapping

The main goal of the CADZIE workpackage 1 is to improve the hazard assessment process by integrating uncertainty and to develop "best-fit" models. This goal can only be achieved if both the stochastic characteristics of the avalanche system as well as the physically describable behaviour are modelled adequately. Although there exist numerous empirical and dynamical models in theory and computational form, till now only few attempts have been carried out to combine these different concepts. The objective of this report is not to develop a new constitutive law for avalanche dynamics or to derive a new statistical function for run-out estimation, but rather to integrate random processes, uncertainty, and also vague knowledge in the system description.EU CADZI

Computational models for dense snow avalanche motion

Seventeen various models of dense snow avalanche motion are presented. These include statistical, comparative and energy considering models for runout distance computations as well as dynamic models for avalanche motion simulations. The latter describe either the internal dynamics of the material at certain stages of the motion, the dynamics of the moving mass as a whole from initiation to rest, or combinations of these. The dynamic models are presented with regard to the physical description of the moving material and to the mathematical and numerical modelling. Most of the dynamic models are rooted in hydraulic theory where the moving masses are described as a fluid, but also granular flow models inheriting geotechnical aspects of soil mechanics are included. Simple (quasi) three-dimensional models exist, but most of the models are still of one and two dimensions. Rather than expanding more existing models into three dimensions, the author suggests to improve the one- and two-dimensional dynamic models further, preferably by combining models based on Bagnold's (1954) concept of dispersive pressure and dynamic shear with granular flow models involving aspects of soil mechanics. Density variations, nonhomogeneous concentration, particle size distribution, cohesion, particle rotation as well as temperature changes and energy dissipation are not adequately described in any of the dynamic models. Furthermore there is a conspicuous lack of any description of stability and accuracy of the applied numerical methods. Examples of travel distance computations based on one statistical, one comparative and three dynamic models are finally presented for four Norwegian avalanches.Norges Forskningsråd (NFR

Exploring patient safety in rural general practice - a mixed-methods approach

Unsafe medical practices and incidents where safety hazards cause harm to patients occur daily in general practice. The costs to society, health care personnel and individual patients are substantial and deserve attention. “Hazards” can be regarded as local error-producing factors, latent failures, which create conditions for unsafe medical practice to take place. “Harm” occurs when these conditions breach safety barriers and reach the patients. Individual doctors who make mistakes created by these factors are most likely to continue to make mistakes until the underlying conditions are remedied. The responsibility for establishing safety barriers in healthcare systems is assigned to health professionals, health organisations and the government. In Norway, there is a general practitioner (GP) scheme involving more than 4700 doctors at present. It includes a patient list system that enables the care of individuals over time, i.e. continuity of care. Continuity varies between municipalities in Norway. In small municipalities, the GP scheme is affected by the frequent use of locums (substitute GPs). Rural GP clinics also face challenges in care provision in terms of vast transportation distances and possible support of secondary care specialists. Little is known about patient safety threats in these clinics, which is the basis for my research for this doctoral dissertation. In the first study we interviewed rural general practice patients and in the third study GPs and other health care personnel. In these studies we asked about their experiences with hazards, harm, patient safety incidents and low quality of care. The second study was a quantitative analysis of disciplinary actions against doctors in Norway in 2011-2018. The doctoral dissertation is based on a mixed-method approach to analyse these results in combination. In paper I and III the participants described many different safety hazards and harm. In paper I patients coped with these conditions by accepting, confronting or planful problem-solving. In paper III the rural general practice staff described how vulnerability for patient safety incidents were linked to frequent use of locums, work overload and contextual factors like bad weather and distance to hospitals. The personnel used knowledge of local context and an awareness to risk of error to hinder patient safety incidents. Results from paper II showed that primary care doctors got 8 times more disciplinary actions than hospital doctors. Rural GPs got relatively most disciplinary actions, 1.7 times more compared to urban GPs. To perform a scientific analysis of qualitative and quantitative results, I have used pragmatism as a theory of science and a mixed-methods design. In brief, this means transforming the quantitative results in Paper II into narrative descriptions. These descriptions are then jointly analysed with the results from Papers I and III. The analysis shows that safety hazards and harm in rural general practice are diverse and seem to occur nation-wide. The causes of harm are both individual and system safety hazards such as frequent use of locum GPs, lack of continuity of care, long distances and high workload. Patients, health care personnel, and the Norwegian Board of Health Supervision (NBHS) are aware of this. Harming patients in rural areas is likely to continue. However, health care workers and patients both help to reduce risks through an awareness of potential safety hazards, the use of local contextual knowledge and confronting errors, especially those made by locum GPs. The method of risk reduction used by the NBHS is system-based by taking disciplinary action against individual doctors based on individual behaviour. Incentives and initiatives from local and national health care leaders to address the safety issues mentioned here and develop safer health care are needed. Greater insight into patient safety in general practice can be revealed through future qualitative, quantitative and mixed-methods studies.Utrygg medisinsk praksis som skader pasienter, forekommer daglig i allmennpraksis. Helsetjenesten i distrikt er påvirket av store reiseavstander for pasientene til legekontoret, og til spesialisthelsetjenesten på sykehus. Lite er imidlertid kjent om pasientsikkerheten ved slike legekontor i distrikt. Vi intervjuet pasienter, og deretter fastleger og helsepersonell som alle bor og jobber i distrikt. Vi har undersøkt deres erfaringer med uheldige hendelser, utrygg medisinsk praksis, pasientskader og lav kvalitet på helseomsorgen. Vi har også gjort en kvantitativ analyse av administrative reaksjoner gitt norske leger mellom 2011-2018. Doktorgraden baserer seg på en mixed-methods tilnærming til disse resultatene. Uheldige hendelser og utrygg medisinsk praksis ved distriktslegekontor er varierte og forekommer antakelig over hele landet. Hyppig bruk av vikarleger, manglende kontinuitet, lang reiseavstand og høy arbeidsbelastning er alle mulige risikofaktorer. Basert på indikasjoner fra trendanalysene, vil skade av pasienter på legekontor i distrikt sannsynligvis fortsette å skje i fremtiden. Flere insentiver og initiativ fra lokale og nasjonale myndigheter trengs for å bedre pasientsikkerheten. Gjennom kvalitativ, kvantitativ og mixed-methods forskning kan man øke forståelsen og bedre kunnskapen om pasientsikkerhet på legekontor i distrikt

EU Programme SAME. A survey of computational models for snow avalanche motion

Various models for computation of avalanche motion are presented, both empirical procedures including statistical and comparative models for runout distance computations as well as dynamics models describing the physics of dense and powder snow avalanches, the coupled combination of these, and slush flows.EU kommisjone