DESIGN AND OPERATION OF REMOTE AVALANCHE CONTROL SYSTEMS (RACS) A BEST-PRACTICE EXAMPLE IN THE ALPS

Walter Steinkogler1*, Paul Dobesberger1 and Sam Wyssen2

1Wyssen Austria GmbH, Innsbruck, Austria 2Wyssen Avalanche Control, Reichenbach, Switzerland

ABSTRACT: This paper gives insights in how to design and operate Remote Avalanche Control Sys-tems (RACS) from the initial project planning to the operational avalanche mitigation by the end-user. Key points that will be discussed and analyzed are important steps during the project planning phase and the challenges local avalanche control teams can have in their decision making. Additionally, approaches and recent (technological) developments with the potential to decrease the corresponding uncertainty are dis-cussed. Therefore, this paper does not necessarily correspond to a “classical description” of a ski resort or highway forecasting operation but represents rather an engineering approach that transitions into the operational tasks of an avalanche control team. Experience has shown that, especially for RACS, plan-ning and operation cannot / must not be considered separately but much more in an integrated approach having the following sentence in mind: “At the right location (= planning) at the right time (= operation) with the right effect (= effectiveness of the system)”.

KEYWORDS: remote avalanche control systems, risk management, design and operation.

1. INTRODUCTION

Throughout history, avalanches have had a major impact on the development of settlements in mountain regions. This influence is obvious from the location and structure of historical villages and traffic routes (Rudolf-Miklau et. al, 2015). A variety of measures has been developed and applied to manage avalanche prone areas in mountainous terrain. Generally, these measures can be separated into active (i.e. preventing ava-lanches from starting and/or changing the likeli-hood) and passive (i.e. measures to mitigate the consequences of avalanche hazard) (Rudolf-Miklau et. al, 2015). Furthermore, defense measures provide either permanent (quasi con-stantly effective) or temporary (time-limited effect) protection. The application of remote avalanche control systems (RACS) and the corresponding operational avalanche control therefore corre-sponds to an active and temporary measure. Note that the document Technical aspects of snow ava-lanche risk management (CAA, 2016 in Chapter 8) refers to active/passive as direct/indirect and to temporary/permanent as short term/long term measures.

The preventive release of snow avalanches by RACS along traffic routes and in ski resorts has been applied since many years if permanent measures appear to be too expensive or not fea-sible to construct for certain areas. Furthermore, the pressure on the avalanche control teams has risen due to the increased mobility demands of societies, such that long-lasting closures of roads and railway lines receive a diminishing level of acceptance.

The technology of RACS and avalanche detection system significantly evolved in recent years. The procedure of planning RACS is often not straight forward and needs to involve a proper project de-sign that considers the specific site conditions, a detailed planning and an optimized placing. This also allows the client to compare between different systems in a more quantitative manner. Experi-ence from the Alps has shown, that specific exper-tise (from engineering offices and the supplier of the system) is crucial to achieve the most user oriented and economic solution. We present (as we believe) „best-practice“ exam-ples and operational experience of RACS for traf-fic route and ski resort applications starting from the initial project design to the final operation by a local avalanche control team. The general tasks and challenges (both on the supplier and client side) are discussed: Initially we analyze the plan-ning and operational phase separately whereas towards the risk treatment phase these steps are more and more integrated to show the “transition”

* Corresponding author address: Walter Steinkogler, Wyssen Austria GmbH, Innsbruck, Austria; tel: +43 664 4373780 email: walter@wyssen.com

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between planning to operational phase ensuring an optimized risk treatment (e.g. planning, startup with new client, seasonal refresher, etc.). Commu-nication is key during all these phases. Both hu-man to human but also between technology and human. The terms artificial and preventive avalanche con-trol are both used in this script and refer to ava-lanche mitigation as active and temporary measure by using RACS. While risk management and its terminology is commonly used (Bründl, 2008) in planning of haz-ard zones and specific guidelines for avalanches exist (Bründl, 2009), it has not been accepted widely (and as common terminology) in the con-text of planning and operative avalanche forecast-ing projects and/or for the design of RACS. Documents as Technical aspects of snow ava-lanche risk management (CAA, 2016) or the ISO 31000 standard in general (ISO, 2009) focus more on WHAT to do, whereas in this paper we try to use examples of operational projects to present HOW to do it in the context of RACS.

2. HAZARD AND RISK IDENTIFICATION

Obviously the main hazard (which is aimed to be mitigated) are avalanches. This hazard affects decisions in the planning phase, during construc-tion as well as during the consequent operation of the RACS. Other relevant hazards related to the mountainous working environment include rock fall and (changing) weather conditions, again both in respect to the project planning and operational phase. Other hazards arise from the wrong usage of the system by staff which could result in potential harm to (other) personnel or equipment. As all RACS are technical, and often very complex, sys-tems a malfunction poses a hazard. The constituents at risk include internal (i.e. Wyssen personnel) and external personnel (i.e. the client staff) as well as material and the reputa-tion of RACS in the industry in general. The overall process of evaluating different mitigation measure, i.e. comparing different systems for preventive avalanche release and/or in combination with stat-ic avalanche defense structures or deflection dams, can also be analyzed in context of the ISO 31000 risk management process (Fig. 1).

Fig. 1: ISO 31000 risk management process.

In the context of this report we focus on more spe-cific risks related to the project planning phase and the operational phase (by the client):

Inaccurate or incomplete project planning, i.e. poorly selected RACS locations, could lead to problems in the operation of the systems and/or a wrong interpretation of the residual risk after miti-gation. Also the (unwanted) triggering of second-ary avalanches needs to be considered. During the operational application of the system the avalanche control team relies their decision on a variety of data sources. Depending on the type of operation the data quality and quantity varies substantially. Therefore, the available information needs to be communicated and available as user-friendly as possible (“technology to end-user communication”) to minimize risks in the decision making. In relation to the usage of RACS the client staff is exposed to the use with explosives, the mis-use/wrong operation of the systems and the trans-portation of RACS components with helicopters. Even though these risks cannot be directly influ-enced by Wyssen they are aimed to be minimized by best-possible training and support to avoid technical difficulties, e.g. duds, or delays in opera-tion.

Other elements at risk, which are not explicitly an-alyzed in this paper, are amongst others:

Wyssen staff is exposed to a variety of hazards during project planning phase, construction as well as technical service and maintenance during win-ter season. Hazards typically include the exposure of staff in mountainous terrain in summer and win-ter, explosives and helicopters. Material and system components of the RACS are often exposed hazards resulting from ava-lanches, rock fall, helicopter transport and improp-

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er handling. Especially in the project planning phase the position of the RACS needs to be se-lected carefully to ensure best-possible effective range and define the structural design (e.g. rein-forced masts). The Wyssen reputation and reputation of RACS in general is at risk by indirect effects. E.g. a han-dling error by the client might lead to the impres-sion that the systems are not working properly. Economic interests of the clients to minimize closure times of traffic routes or ski pistes.

Construction of new avalanche towers usually takes place in late summer and fall. As most RACS are constructed in high alpine areas the weather conditions can substantially influence the construction works. Unfavorable weather condi-tions and early snow fall can increase pressure on the workers and increase their exposure to ava-lanches at their work place. Furthermore, the envi-ronmental conditions could lead to a delay or improperly performed construction (e.g. pour-ing and hardening of concrete) of the tower foun-dations.

3. DATA AND EVIDENCE

Depending on the project area and type of opera-tion (highway, ski resort, construction site, etc.) a varying amount of data and evidence will be avail-able both during the project planning as well as in the operational phase.

Project planning phase: Historic data is often one of the most important pieces of information during the project planning phase. Pictures of historic avalanches or the ef-fects of past avalanches on the vegetation along or adjacent to the path allow to draw conclusions about the magnitude and return period of ava-lanches (CAA, 2002). If avalanche control was already performed in the area, e.g. by helicopter blasting, the information from the local avalanche control team provides crucial information. Previously affected blasting points, typical snow distribution patterns and pecu-liarities of the area or avalanche path are valuable information. Ideally the meetings with the local avalanche con-trol team and decision makers are arranged during a field visit in the project area. These field visits are absolutely mandatory to identify the release areas and consequently the positions of the RACS. Visits in winter help to identify snow distri-bution patters and areas with increased avalanche activity. In the summer, the local topography and geology need to be taken into account to finalize

the RACS positions. Analysis based on Geographic Information Sys-tems (GIS) have proven to be a very effective tool for the best-possible design (number and position of systems) and depicts an excellent tool for com-munication between the involved parties (Fig. 2). For this analysis a digital elevation model is used and a viewshed analysis (= ”what a detonated charge would see within a certain radius”) is per-formed at the points of the planned RACS. This is a very illustrative way to identify possible areas that are not affected, either due to explosive shad-ows caused by the terrain or the maximum effec-tive range of the system. Overlaying the results on a map or orthophoto of the area allows to directly discuss and optimize the project during the plan-ning phase. This helps to optimize the amount and distance between the RACS to avoid unnecessary (and often not-cost-efficient) overlap, unless de-sired as additional backup, of the effective ranges between the RACS positions (blue areas in Fig. 2 indicate overlap). Furthermore, a GIS analysis al-lows for a more quantitative comparison between different RACS systems (and their effective rang-es). Data from automatic weather stations (AWS) which are situated close by can help to estimate the (new) snow amounts and prevailing wind di-rections. Yet, it needs to be assured that the data recorded at the AWS location are representative for the project area. Although more typically used for hazard mapping purpose, the application of avalanche dynamics models can help to specify flow patterns of ava-lanches.

Fig. 2: 3D view of release areas with 6 RACS

(stars) on the ridge. Effective blast radius (red, 130 m radius) overlap of effective ranges of individual RACS (blue).

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Operational phase: During the operational use of the RACS the local avalanche control team bases their decision on rather “traditional” sources of information (not all discussed here). Yet, due to specific challenges while performing preventive avalanche control specific technology, e.g. weather station sensors on the avalanche towers and detection systems, can support their decision making. Automatic weather stations (AWS) are a com-mon information source for the local avalanche control team to continuously receive information from the alpine areas and is often one of the few data sources during storms. The progress in tech-nology in the last few years facilitated to access all this information in user-friendly ways and user-oriented solutions, such as to provide additional weather station sensors directly at the RACS loca-tion. Local observations such as periodically per-formed manual snow profiles can be supplement-ed with snow profiles from computer models, e.g. the Swiss model SNOWPACK, to supplement pe-riods without snow cover observations. Avalanche activity in similar or close by avalanche paths as well as the positive or negative result of artificial avalanche release can be interpreted as signs of instability. The special requirements for the application of RACS, especially for many highway operations, requests not only the confirmation of the detona-tion of the charge at the RACS location but also if an avalanche was released. This can be a chal-lenge, especially during a storm and/or at night. Therefore, avalanche detection systems, such as radar, geophones and infrasound systems, provide an essential decision tool for the ava-lanche control teams.

3.1 Strength and weight of evidence

Project planning phase: For most project areas the quantity and quality of the available data sources as described above will vary. Therefore, the available information need to be evaluated carefully with respect to their strength and weight. Historic data covering a long period of time allows to draw conclusions on the typical size of an ava-lanche (strength) and how often an avalanche of a certain size runs certain areas and run-out dis-tances of the avalanche path (weight). Field visits during the summer and winter give a very good overview of the location and the current situation (high strength). Yet, it is always only an

observation of the current conditions therefore its weight is less compared to the historic data.

Similar assumptions can be made for the infor-mation of local decision makers such as an ava-lanche control team that was performing avalanche release with explosives already for a certain amount of time. They might have observed and identified certain characteristics of the project area. Even though this information has high strength, the often relatively short work time (e.g. only 5-10 years) results in less weight. Impressive or extraordinary (and therefore memorable ava-lanches) but isolated avalanche events might even cause a bias in the judgement of the local condi-tions by the local decision makers. Weather station data can be used to determine the main wind direction in the area (strength) but local wind deflections can cause very different snow (re-)distribution patters in the release area and these data need to be interpreted carefully (weight). Avalanche dynamics calculations can help to iden-tify flow directions and estimate run-out distances. Yet, currently applied models are not always suit-able for the calculation of smaller sized, i.e. artifi-cially released, avalanches. Even though these models are well established and suitable tools in hazard mapping their results (and weight) need to be interpreted with care in the context of RACS planning. The presented GIS analysis allows to integrate all the available and relevant (high strength and weight) information into a single document. It therefore can have a very strong weight in the pro-ject planning phase. Generally, it not only helps to idealize the locations of RACS but also to create a planning tool that allows excellent communication with the client and/or engineering office. A GIS analysis itself, i.e. without taking into ac-count the historic, local and field visit information, might have high strength but should have low weight in the overall planning.

Operational phase: Avalanche control teams in ski resort usually have a substantial amount of data and observations with high strength and high weight. E.g. after per-forming numerous detonations with hand chargers or RACS they get direct feedback about the snow cover stability and thus information of high strength (direct information on avalanche activity / release potential) and weight (large amount of ob-servations). Furthermore, they have the potential to cover and overview their operations area rela-tively frequent (on a daily basis). Highway operations on the other hand typically

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have limited observations (less weight) especially from higher elevations and the release areas. They need to base their decisions on much less data. Especially for those cases technical tools such as automatic weather stations, avalanche detection systems, snow cover modeling, etc. can increase the amount of available observations (and thus increase the weight of the information from the release area).

3.2 Confidence and uncertainty

Depending on the project area and the client’s op-eration (highway, ski resorts, construction site) the quality and quantity of information will strongly vary. Experience has shown that an integrated estimate from the various data sources and meth-ods will result in the most client- oriented solution with the highest confidence. Not all methods are always applicable or available for the project and the consequent avalanche paths.

Project planning phase: Depending on the available information in the pro-ject area the combination of historic local infor-mation, the input of the local avalanche commission, field visits and GIS analysis allows to increase confidence for the project design. Especially for projects in new areas (different to-pography and snow climates) it can be difficult to establish a data base with high strength (relevant observations and data) and weight (quantity and quality of reliable data of data). In this situations the communication with local avalanche control teams and decision makers is even more im-portant.

Operational phase: Since the operational application of active ava-lanche control is a task with high responsibility the pressure on the avalanche control team, e.g. due to road closure, can be substantial. For highway operations the uncertainty in decision making can be larger due to a reduced amount of data, compared to ski resort operations, especially for the elevations of the release areas. In those cases, additional measurements such as (new) snow depth, wind and/or air temperature directly in the release area at the RACS can provide an addi-tional data source with both high strength (local conditions in the release area; if a certain thresh-old is exceeded) and high weight (continuous measurement).

Fig. 3: Incorporating detection systems in an easy

to understand way into a single platform.

Even though a detonation confirmation at the RACS location ensures the avalanche control team that they affected the snow cover in the re-lease area, it is often not possible to determine if an avalanche was released. Especially during stormy conditions and/or at night avalanche detec-tion systems provide evidence of high strength. Fig. 3 for example shows the application of geo-phones (yellow circles) and radar detection (rec-tangular boxes filled with red circles) in an avalanche operation in Switzerland. The ava-lanche control team successively activated the RACS in the release areas (black circles) and re-ceived immediate confirmation of detonation as well as avalanche release (colored areas in geo-phone and radar sectors). Even though they had no visual contact to the path or release area this information allowed them to conclude that (1) all release areas were affected by detonations and (2) the avalanches were released, entered the main gully, but did not reach the road below. They could therefore re-open the road with high confi-dence and very little uncertainty (residual risk).

4. RISK ANALYSIS AND EVALUATION

A variety of risks were identified in the Section 2. In this section we will now analyze and evaluate selected risks during the project planning phase due to planning errors and for the operational phase due to improper handling of the equipment by external/client staff.

Project planning phase: Two of the main aims of preventive avalanche re-lease is the release of snow from the release are-as in small portions and to prevent natural avalanches. Therefore, improper project planning can result in the fact that not all defined and relevant release areas are affected. This could have the conse-

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quence that snow accumulates and weak layers develop over the season that are never affected by explosives or other avalanches. The likelihood due to improper design of the RACS locations and positions is quite substantial and the consequences can be very cost intensive (additional installation or repositioning of RACS).

Operational phase: To operate the systems, the avalanche control team bases their decision on a varying amount of data to define the time of the avalanche mitigation measures, e.g. weather forecast, automatic weather stations, etc., and to verify the success of the measures, e.g. detonation confirmation, ava-lanche detection with radar, etc. Both a wrong timing of the avalanche control as well as the (non-)possibility to verify the avalanche release can have serious consequences on the object to protect, e.g. traffic route, as the system might have been “used” but in fact the residual avalanche risk was not mitigated or reduced. In terms of operation of the RAC system and its seasonal preparation multiple risks exist. For ex-ample, an unexploded charge (dud) exhibits a challenge due to several reasons: the defined re-lease area was not affected by a detonation (thus the avalanche hazard was not mitigated), the dud needs to be recovered and it can result in a sub-stantial delay of operations and re-opening of the ski piste or road. Even though the malfunction of the explosives or detonators is small (a statistical evaluation has shown a percentage of 0.3 %) the largest source of error lies in the preparation of the explosives and loading of the magazines at the season start. Even though the likelihood of a dud is very small the consequences can be very large and therefore continuous effort is invested to improve this pro-cedure.

5. RISK TREATMENT AND CONTROL METHODS – BOTH FIELD AND OFFICE

Project planning phase: Risk treatment in terms of project planning com-prises well-structured workflows, direct and open communication with the involved clients and/or engineering offices. Defining the project area in-cludes a proper definition of the release areas (not only historically used blasting points) that need to be affected, the avalanche path and the object to protect (traffic route, ski piste, etc.). A company internal (Wyssen) policy of not finaliz-ing the position of a planned RACS location before “standing in person at the planned location” en-sures the mandatory field visits and meetings with

local decision makers. The integrated processing of the available infor-mation ensures a best-possible position of RACS and that all defined release areas are affected, ultimately changing the likelihood (disturbing weak layers) and consequence (reducing the amount of snow) of avalanche hazard of that area and path. Events that are severe (high negative conse-quence) but rare (low likelihood) could be caused for example if the installed RACS fail be-fore or during usage by the avalanche control team. For projects where a backup is desired a predefined overlap of the effective ranges can en-sure that the release areas are still nearly com-pletely affected even if one RACS fails. Furthermore, independent connection possibilities (dual connection via mobile network and radio) to every individual RACS ensure that the system can be controlled even if one connection fails, e.g. in a catastrophic scenario where the mobile phone network collapses.

Operational phase: During the operational use of the RACS by the client, risk treatment options cannot be directly or only partly controlled by Wyssen. Yet, the risk re-sulting from improper use or decision making can be antagonized indirectly. First the technology supplied to the end-user needs to be as user-friendly and without ambiguity as possible. Especially during relatively stressful times of avalanche control the communication be-tween technology and user has to be as direct as possible. For example, the user must be able to determine the readiness of the system, the activity during operation and the confirmation of a detona-tion in a simple and efficient way. Furthermore, the diversity of (more or less relevant) information for decision making needs to be focused on the es-sential (with most strength and weight) data. For example the interpretation of measurements from avalanche detection systems need to be combined in a single and easy to interpret platform (Fig. 3) to allow a correct and fast decision making for the avalanche control team. Improvements in technology further allows to con-stantly monitor the state of the system by the sup-plier. To some extent this takes away the need of the client to constantly monitor the system. Thresholds, e.g. battery power, can be monitored and predefined thresholds inform the user and/or the service team of the supplier about any abnor-malities. To change the likelihood of a wrong usage of the system and to incorporate risk treatment options in

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the daily workflows of the avalanche control teams refresher meetings during the seasonal mainte-nance of the deployment boxes by Wyssen tech-nicians have proven to be very successful. During this time the client can be re-trained in the han-dling of the system, the explosives preparation and the loading of the deployment boxes. The continuous improvement of the system, both in terms of technology such as hardware and in-teraction with the user, allows to remove risk sources and increase the reliability of the system (this corresponds to reviewing and monitoring in Fig. 1).

5.1 Evaluate and manage exposure and vulnerability

The aim of a proper project planning phase is to reduce the avalanche hazard after performing ava-lanche control with the RACS to an acceptable risk level (predefined in the project planning phase with the client). In operational words this means that after using the RACS, assuming the actions where performed with correct timing, the ava-lanche control team either released the accumu-lated snow in the release area and/or affected the snow cover and potentially existing weak layer sufficiently enough, such that they can suppose a consequent natural release to be unlikely. In terms of operational usage of the system a key advantage of RACS is to “decouple” the exposure to the usage of explosives and traveling in ava-lanche terrain in often demanding weather condi-tions combined with the stress to perform avalanche control as fast as possible. All direct handling of explosives (preparation, loading into the system and transportation to the final location of usage) is performed before the season. This allows the avalanche control team to “only focus” on the handling of the avalanche hazard and per-form their work as efficient as possible.

5.2 Effectiveness of risk treatment and actual risk reduction achieved

Project planning phase: During the project planning phase, a predefined workflow ensures the consideration of all neces-sary (and available) information. Typically, the po-sitioning of the RACS starts with a very rough and initial analysis and is then consequently adapted and developed in collaboration with the client and field visits. In relation to the ISO 31000 risk man-agement the steps of Risk Evaluation and Treat-ment (Fig. 1) are typically iterated multiple times until the final stage is achieved. Especially for new clients and during the first year

of operation a continuous check-in with the ava-lanche control team and the decision makers is actively performed to review the effectiveness of the taken measures. Often small adaptions and optimizations to the client’s needs and operation, e.g. adapting thresholds of the detection system or adaptions to the user- interface to control the RACS, can further increase the effectiveness in their working routines.

Operational phase: Every year Wyssen technicians perform the yearly maintenance on the deployment boxes of the Wyssen Avalanche tower. Ideally and very often these maintenance periods are combined with a refresher on the system components and prepara-tion, assembly of the explosives and loading of the deployment boxes. Regular visits or working with the avalanche con-trol teams allows to identify emerging risks or until then not identified risks and their consequent reac-tion. This direct feedback with the client also al-lows to improve the system to a more and more user-oriented system. From the client side a pre-season check of the project is recommended as certain elements at risk might have changed or were added after the preceding season (e.g. a new piste was added during the summer and now needs to be consid-ered during the operation of the system). This again emphasizes the link between planning and operational phase and the need for an (continu-ously) integrated approach.

5.3 Risk communication to target audience – key messages

In the projecting phase a clear communication with maps, illustrations and documents combined with field visits and meetings is paramount. Especially the maps and 3D views generated with the pre-sented GIS analysis (Fig. 2) has proven to ensure a clear communication and minimizes misunder-standings both in the field and office meetings. At the yearly maintenance a direct contact with the avalanche control team is pursued. Key infor-mation about the system is again communicated and this step also helps to encourage the person-nel to use the provide 24/7 hotline if questions should arise (“knowing people face to face”). With new clients a detailed start-up introduction is performed. This is typically performed at the time when the system is loaded with explosives and transported to the avalanche towers via helicopter. This insures a “real” training environment for the (new) client and allows to define and illustrate the best-possible procedures by the Wyssen person-

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nel. In addition to the 24/7 service hotline which is pro-vided to the client substantial effort was put into the manual of the system which also serves as a reference book and contains all necessary steps for the client to prepare and operate the system.

6. CHANGES TO OPERATIONS THAT WILL IMPROVE RISK CONTROL IN FUTURE

Technology: In our company the continuous de-velopment of the Wyssen Avalanche Control Cen-ter WAC.3 has been shown to substantially improve risk control as Wyssen can continuously monitor the system and identify/solve possible problems beforehand. For example, the continu-ous monitoring of all relevant system variables, such as battery power, allows to intervene before a problem emerges and in the worst case the sys-tem would not work during an avalanche control operation. Creating user-friendly and user-oriented solution has shown to substantially increase the acceptance of new technology and improve the daily workflow of the avalanche control teams.

Planning tools: The presented GIS analysis is an excellent tool to communicate with the client and engineering offices during the project planning phase and to optimize the amount and location of RACS. Therefore, the usage of this kind of analy-sis will be further developed and encouraged throughout the varying (international) projects in the company as well as in the industry in general.

Training & Communication: The (seasonal refresh-ing) training of internal (Wyssen) and external (cli-ent, engineering offices) personnel will be continued and, along with the evolution in technol-ogy, refined.

7. SUMMARY AND CONCLUSIONS

Communication is key – both in the project plan-ning and the operational phase! Particularly, a very open communication (from client side too) is mandatory and needs to be allowed (and encour-aged). New (technological) developments and concepts, in planning and operations, need time to be ac-cepted in the industry. Open minded and well trained clients are very suitable to apply them in their operational environment for the first time and eventually substantially help to make them an in-dustry standard (see the Gonda example at the Wyssen homepage).

Safety of workers and proper project planning must overbalance economic interests in any situa-

tion. A consolidated knowledge on the effective range of the RACS has to be communicated to the client in an accurate, faithful and comparable way (e.g. in a GIS analysis). Advances in technology can help the avalanche control teams in their decision making. E.g. mete-orological sensors on the RACS directly in the re-lease allow to receive information from higher elevations where data is usually sparse. Avalanche detection systems and their incorpora-tion into user-oriented platforms allow for a fast and efficient operation of the avalanche control and reduces the uncertainty in the decision mak-ing of the local decision makers.

CONFLICT OF INTEREST

All authors of this paper are involved with devel-opment and sales of avalanche detection systems and Remote Avalanche Control Systems (RACS).

ACKNOWLEDGEMENTS

The content of this proceeding is part of CAA Level 3 report and the authors want to thank Christoph Mitterer, Jan-Thomas Fischer and Stian Langeland for proof-reading.

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Canadian Avalanche Association, 2002: Guidelines for Ava-lanche Risk Determination and Mapping in Canada. McClung, D.M., C.J. Stethem, P.A. Schaerer and J.B. Ja-mieson, (eds.). Canadian Avalanche Association, Revel-stoke, BC.

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