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Interpretation Guide as a .pdf file. Links ¶ White Risk Portal White Risk SLF on Twitter White Risk SLF on Facebook White Risk SLF on Instagram Avalanche bulletins around Europe Glossary Natural Hazards [...] bulletin is produced? White Risk: the avalanche app Avalanche bulletin, snow data and much more. User-friendly and free: the SLF's avalanche app Avalanche bulletin survey Support the further development of [...] bulletin is an official federal warning issued by the WSL Institute for Snow and Avalanche Research SLF. It is described on this website and in the avalanche bulletin interpretation guide, whereby only the

spent two months at the SLF. His aim was to test a new method to measure thawing permafrost. The challenge: getting around 150 kg of equipment up to high mountain test sites. SLF researcher Alexander Bast [...] site at Schafberg above Pontresina (GR). Photo: C. Hoffmann, SLF During Summer 2019, I carried out several geophysical tests together with the SLF Permafrost Group. Our aim was to explore permafrost, permanently [...] the conductivity of the substrate without contact. Image: C. Hoffmann, SLF Download The electro-magnetometer. Image: C. Hoffmann, SLF (jpg, 320 KB) Fullscreen Image 2 of 8 During the measurements, Jacopo

ETH Domain, has digitized and published over 700 SLF reports. 16.12.2024 Wind modifies snow crystals – and climate models Experiments conducted by the SLF show how wind transforms snow crystals. The findings [...] complex material, natural hazard, economic resource or part of the global climate system – at the SLF we investigate all these aspects of snow. At first glance, snow may appear to be simply a homogeneous [...] changes. More recently, we have increasingly been supplementing ground measurements with remote sensing data from satellites, aircraft and drones, which also provides information on the large-scale distribution

forecasting. Modeling at the SLF At the SLF too models are becoming more and more important and represent now a very significant part of the research performed at the institute. The SLF uses models in order to [...] functions are derived from a great volume of collected data, which is derived from observations of the factual relationships. Based on a huge volume of data from automatic snow and weather stations, we can, [...] turn, is based on a physical process, e.g. diffusion, melting processes or heat conduction. At the SLF, we model the snowpack to better understand avalanches. The SNOWPACK snow cover model was designed

observation bunker is unmanned and the measured data is transferred directly to the SLF in Davos where staff scientists analyze the data. The recorded data from spontaneous avalanches has been especially [...] essential data to understand and model avalanche motion. The site has been in operation since the winter 1997/98 and represents the cornerstone of snow avalanche dynamics research at the SLF. Partly destroyed [...] release of one or more of the release zones. A group of SLF scientists and engineers is placed on standby, typically three days before the event. SLF experts in Sion and Davos watch the weather closely before

technology. We use different types of numerical models to calculate snow water resources based on input data from meteorological monitoring networks. These models are being used to predict the consequences of [...] Conducting ongoing analyses of the spatial and temporal distribution of snow water resources, the SLF's operational snow-hydrological service (OSHD) heightens the accuracy of hydrological forecasting. [...] forest Both snow distribution and snow melt patterns are much more variable in the forest than in open terrain. We are examining the influence of the forest on water availability in subalpine drainage

Instrumented field sites and laboratories ¶ Experiments are at the heart of SLF's research. However, these experiments are only possible using well-equipped outdoor field sites and laboratories. The Swiss [...] of these sites for decades – for example at our Weissfluhjoch test site . Only with these long-term data series are we able to show how our environment is changing on a long-term basis. In addition to the

between man-made structures and avalanches. Foto: Pierre Huguenin, SLF Modelling snow avalanches ¶ The acquired know-how and collected data are used to develop avalanche dynamics models to study the interaction [...] is compared with data collected with a high-speed camera. Right: simulation of the Dorfberg avalanche, Davos, using the material point method (MPM). Simulation: Michael Kyburz, SLF Topics ¶ Full-scale [...] the development of practical computational tools such as the RAMMS model by providing calibration data and basic knowhow, and we develop and test new computational methodologies to continuously improve

the automated IMIS snow stations of the SLF. Fresh snow plays a key role in the formation of avalanches. The map shows the most recent available value for each data point. If the most recent measurement [...] Information about snow measurement ¶ Snow measurements are taken on flat, wind-protected sites of the SLF and MeteoSwiss. Snow depth is measured either manually or automatically. The chart tracking snow depth [...] station is greyed out and depicted without a value. Some of the depicted values originate from raw data that have not been checked or validated. Manual measuring sites ¶ Snow depth and fresh snow are measured

4 Arctic terns nest in large numbers on Samoylov. Photo: Christian Rixen, SLF Download Arctic tern. Photo: Christian Rixen, SLF (jpg, 128 KB) Fullscreen Image 4 of 4 You need to watch out for Arctic terns’ [...] on their territory, aiming for their heads! Photo: Christian Rixen, SLF Download Arctic tern attacking. Photo: Christian Rixen, SLF (jpg, 94 KB) A long wait followed by a sudden panic That evening, we [...] plant properties such as the areas of leaves, and collected data at the soil surface that could be analysed together with drone and satellite data. My luggage even turned up in the end. Fortunately, I had

can arise when high melt rates in the catchment zone combine with heavy rain. For this reason, the SLF runs an operational snow-hydrological service (OSHD), which predicts meltwater volumes. This contributes [...] on runoff. Snow in the forest Snowpack accumulates and melts differently in forests compared with open areas. Tree canopies, for example, can intercept precipitation and absorb radiation. Since forests [...] Conducting ongoing analyses of the spatial and temporal distribution of snow water resources, the SLF's operational snow-hydrological service (OSHD) heightens the accuracy of hydrological forecasting.

New Zealand, took part in the MOSAiC expedition in 2019/2020. Her time at the SLF will mostly be spent evaluating the data obtained during the expedition. In this blog she charts the pitfalls faced by [...] elevation models from the Arctic ¶ The reason for my fellowship is to work closer with SLF colleagues on MOSAiC data. I was mainly working on generating high-resolution small-scales digital elevation models [...] kids at three different "schools." However, the help and support we got from the colleagues at the SLF and teachers were beyond amazing, so we got into the new routines quite quickly. By Christmas, the

visit to collect data during snowmelt and spring warming was at the right time. Photo 5. The Kitinen River ice breaks up near the Sodankylä town center. Photo by Giulia Mazzotti (SLF/MeteoFrance). Related [...] Arctic Research Center through thermal drone imagery and melting river ice. Photo 1. Vincent Haagmans (SLF/WSL) and Cassie Lumbrazo (UiO/UW) send the Autel drone off for a flight over our study site. After [...] other canopy elements, they remain warm well into the night (Photo 2; Video 1). Photo 2. Tobias Jonas (SLF/WSL) in the forest after sunset taking ground based thermal measurements. Video 1. A screen captured

¶ Every avalanche observed in Davos since the winter of 1949/50 has been recorded and mapped. The data spanning all those years constitute a very valuable resource for avalanche researchers, and one that [...] anywhere in the world. Fig. 1: The avalanches are mapped in the red bordered area around Davos. Picture: SLF Who benefits from this mapping? Avalanche activity is a very important factor for both avalanche f [...] Davos recorded? The outlines of observed avalanches are recorded in close cooperation between the SLF and the rescue services of the mountain railways/cableways as well as the commune's avalanche warning

which avalanches occur (SLF archive) The early days and the contribution of Adolf Voellmy ¶ Figure 2: In Vals, an entire part of a village was destroyed in the winter of 1950/51 (SLF archive). Avalanche research [...] Vallée de la Sionne avalanche test site – view of the bunker after an avalanche release (SLF archive). In 1997 the SLF initiated construction of an extensive avalanche test site in Vallée de la Sionne (Fig [...] with actual large avalanches. The future ¶ Figure 6: RAMMS workshop in India (SLF archive). The research activities of the SLF in the field of avalanche dynamics now span three generations and have given

Caduff-Fiddes / SLF) Yves skiing down in “big turn powder” (Video: Joel Caduff-Fiddes / SLF) Yves crossing the tracks in the refrozen mush from the day before. (Photo: Joel Caduff-Fiddes / SLF) However, we [...] launches the drone! (Video: Joel Caduff-Fiddes / SLF) CROMO-ADAPT colleague Sultan Belekov from Kyrgyz Hydromet launches the drone! (Video: Joel Caduff-Fiddes / SLF) Too-Ashuu pass 3400 m a.s.l. ¶ At Too-Ashuu [...] Bühler / SLF) National park Ala Archa ¶ Flight preparations in the Ala Artscha national park. In the valley the high wind speeds a few meters upslope was not recognizable. (Photo: Yves Bühler / SLF) The next

e for their own safety in this "open terrain". With basic knowledge, simple concepts and tools, the risk of avalanches can be minimised to an acceptable level. The SLF recommends that freeriders and ski

©WSL-Institut für Schnee- und Lawinenforschung SLF Die Schnee-Detektive: 80 Jahre Gespür für Schnee, Einstein vom 11. Februar 2016 Murgangforschung im Illgraben SLF: Lawinen-Grossversuch im Wallis [...] advantage: they allow us to study natural hazards on a realistic scale and under natural conditions. The SLF has several such large-scale instrumented field sites: In Valléé de la Sionne (Arbaz, Valais), we can [...] dynamics test site Vallée de la Sionne (VdlS) is providing scientists and engineers with essential data to understand and model avalanche motion. Debris-flow observation station Since 2000 the WSL has been

yourself. Photo: Yves Bühler, SLF There is no such thing as 'fixed points' because everything is on the move. We've been working intensively with the satellite, aircraft and drone data from Davos, analysing, [...] Milford Road – perfect conditions for extreme avalanches. Photo: Yves Bühler, SLF Download Milford Road. Photo: Yves Bühler, SLF (jpg, 9 MB) Fullscreen Image 2 of 3 A sign warns against entering the avalanche [...] this kea (the world's only mountain parrot species) can fly. Photo: Yves Bühler, SLF Download Kea. Photo: Yves Bühler, SLF (jpg, 8 MB) Fullscreen Image 3 of 3 Our awestruck Swiss avalanche researcher on

meanders through the prairie landscape of Central Otago. Photo: Yves Bühler, SLF Download Clutha river. Photo: Yves Bühler, SLF (jpg, 4 MB) Fullscreen Image 2 of 4 Bye bye helicopter! Now we're on our own [...] with no mobile phone reception anywhere in this region. Photo: Yves Bühler, SLF Download Helicopter. Photo: Yves Bühler, SLF (jpg, 7 MB) Fullscreen Image 3 of 4 Our camp at the foot of Mount Brewster (with [...] the background) and the glacier under thick snow. Photo: Yves Bühler, SLF Download Camp a Mount Brewster. Photo: Yves Bühler, SLF (jpg, 2 MB) Fullscreen Image 4 of 4 The view from the summit of the unspoilt

Figure 4: Experimental defences erected by the SLF – in 1955 trials took place with snow nets to prevent gliding snow (SLF archive). Figure 5: In 1952 the SLF erected experimental defences on the Dorfberg [...] Platform (GIN) developed by the SLF has established a further benchmark. For the first time, the federal agencies responsible for natural hazards (the FOEN, MeteoSwiss, the SLF and the SED) are now posting [...] had been built were too low to afford effective protection (Fig. 3). As long ago as around 1939, the SLF published the first ground-breaking insights into calculating snow pressure, and erected experimental

Tamina Gorge in Bad Ragaz. Missing: Martin Moritzi und Jacqueline Annen Approach The WSL values active, open and honest communication. The public must be able to know – and should know – what research their [...] Andrin Valsangiacomo Outreach, Editorial staff DIAGONAL, news editor, events Communication Davos, SLF Cornelia Accola-Gansner Group leader Jochen Bettzieche-Keber Editorial management DIAGONAL, responsible [...] publishing Delia Landolt Media relations, visitor tours, web publishing Roman Oester Responsible for slf.ch and social media Publications (Web & Print) Sandra Gurzeler Group and Online Team leader, layout

effort needed to gather our data. At the same time, working together so intensively made a family out of individual team members. Fullscreen Image 1 of 7 The ice cracked open next to our remote sensing [...] Central Arctic during April. However, the great dataset did not come for free. One day the ice cracked open around our observation site and we had to rush to save our equipment. Relocating the installation [...] With the new site closer to the ship and on more stable ice we were finally able to collect a lot of data. Download ELBARAAtNewRSSite (jpeg, 196 KB) Fullscreen Image 6 of 7 We had a cold lab on the ship,

"Current avalanches" view on whiterisk.ch displays manually mapped avalanches. These are reported by SLF observers and the public . This information is neither verified nor corrected and may be inaccurate [...] moisture refers to the liquid water content of the snowpack in the starting zone. Interpreting the data ¶ The "Current avalanches" displayed are only some of the avalanches that occur. While in some areas [...] area, there may be various reasons for this: Favourable avalanche situation Poor visibility No active SLF observers in the area Uninhabited, poorly visible area Few winter sports enthusiasts in the area and

consideration in the next assessment. Other reporting options: White Risk App E-mail to bulletin(at)slf.ch Freephone number 0800 800 187 Note on avalanche bulletins in summer and autumn ¶ In the summer and [...] and autumn, avalanche bulletins are published only in the event of heavy snowfall. Even if the SLF does not publish an avalanche bulletin, due consideration is to be given to the avalanche situation especially [...] much fresh snow has fallen, and where? How deep and stable is the snowpack? Measured values A bevy of data retrievable any time, filtered by station altitude. AvaBlog The current avalanche situation analysed

weather was stable and our team was very much ready to collect the data we needed. Average winter, early melt ¶ The measurement data show that winter 2019/2020 was not so bad for Swiss glaciers, despite [...] survey in late winter is intended to determine snowfall, while the September survey measures melt. Some data series go back more than 100 years and were even continued during both world wars, so we have a duty [...] Although we had to do without some of our heavy measuring devices, we were still able to collect vital data, thus ensuring the continuity of the series. The support of the Swiss military was a stroke of luck

and fracture depths. The SLF has developed an algorithm to identify potential avalanche starting zones on the basis of terrain parameters. It was validated using a reference data set for three areas in the [...] mapping for avalanches ¶ To calculate and visualize the potential avalanche hazard, researchers at the SLF have developed a method that automatically and efficiently pinpoints avalanche starting zones. They [...] hazard maps already exist. These have been produced on the basis of land registry information, climate data, terrain analyses and numerical simulations of avalanche dynamics. Hazard mapping by experienced

Avalanche bulletin The hazard map is zoomable. Clicking the map highlights the corresponding regions and opens a window containing the relevant danger description and the text on Snowpack and weather. The hazard [...] map showing only the danger level. Supporting products ¶ In addition to the avalanche bulletin, the SLF publishes numerous supporting products, such as snow maps, measurements recorded at snow stations,

ensure precision, the model integrates station data, high-resolution meteorological forcing data, and various reanalysis products, employing cutting-edge data assimilation and meteorological downscaling methods [...] Snow-hydrological forecasting ¶ The SLF maintains an operational snow-hydrological service (OSHD) that continuously provides analyses and forecasts of the spatial and temporal distribution of snow water [...] contribute to national and cantonal hydrological forecasting, natural hazard mitigation, and provide data for partner services such as the weather forecast by MeteoSwiss and our in-house avalanche warning

the formation of slab avalanches (SLF archive). Figure 2: One of the first instruments developed for field measurements by the pioneers was the ram penetrometer (SLF archive). Figure 3: The snow micro [...] Schweizer/SLF) Figure 6: Snowpack simulation with the SNOWPACK model. The simulation complements manual snowpack investigations; it temporally and spatially consolidates the available snowpack data and, in [...] the penetration resistance as the probe is driven into the snow by a motor (photo: Jürg Schweizer/SLF). Figure 4: The rutschblock test is the mother of all snowpack tests. It resolves several questions:

collect data here. To develop new algorithms to automatically find avalanches, we rely on data from our system in Davos. With the new system in Iceland, we will have completely independent data to evaluate [...] Iceland - despite many volcanoes and earthquakes. The data obtained from Iceland will also help to improve the algorithms and thus the system. At SLF, we therefore recently initiated a project to develop [...] conditions. Alec van Herwijnen, head of the Avalanche Formation and Dynamics research group at the SLF, is spending a sabbatical in Iceland with his family. There he wants to investigate whether an avalanche

n provided by the SLF does not relieve users of their obligation to assess the avalanche situation for themselves on the ground and to act accordingly – see the disclaimer on www.slf.ch, www.whiterisk [...] the very nature of forecasting means that the predictions made may prove to be incorrect. While the SLF makes every effort to ensure the accuracy of the website content and information and the White Risk [...] south of the main Alpine ridge demand special scrutiny because in most instances, compared to the data on intermediate and high altitudes in other regions, less information is available in these places

service. By 1950, 20 observers were providing weather, snow and avalanche data to the avalanche warning service. Each week, the SLF issued an avalanche bulletin on the radio and in the press. This information [...] four languages used by the SLF (German, French, Italian and English), for all the forecast areas. This was only made possible by various elaborate systems developed at the SLF, including a fully automatic [...] Bern Following the end of the Second World War, the WSL Institute for Snow and Avalanche Research (SLF) spawned by the Commission took over responsibility for avalanche warnings on 1 October 1945 and e

displayed daily on www.treenet.info/nowcasts . These data are also integrated in the federal NCCS site on forest functions and climate change , where further data on current forest condition can be compared in [...] consequences for agriculture, water supply, energy production or natural ecosystems. We are creating the data basis to recognize critical droughts at an early stage and to assess and mitigate their consequences [...] government for drought in Switzerland ( www.drought.admin.ch ) combines a wide range of hydrological data in a Switzerland-wide early detection system for drought. On our drought.ch platform, we develop models

n concerning the current avalanche situation and warns the public about the avalanche danger. The data underlying the service is delivered by an extensive network of observers and automatic measuring stations [...] used in the unit's intensive teaching and training activities. It works closely together with other SLF research units and partners in Switzerland and abroad. These include national and international research [...] responsible for public safety and tourism. Topics ¶ Avalanche bulletin In its avalanche bulletins, the SLF provides information about the current avalanche situation. Its content is designed as an informed

a warm snap. Weak layers, such as snow-covered surface hoar, can increase the risk of avalanches. SLF observers therefore monitor their development closely. To improve avalanche risk forecasting, we are [...] Corina Lardelli, right image: Jürg Rocco We investigate the fundamentals of snow drift in detail at the SLF's wind tunnel facility and at test sites. The measurement results feed into computer models , which [...] SNOWPACK model simulates the development of the snowpack during the winter, based on meteorological input data. Snow transport In a wind tunnel and at measuring sites we investigate where snow is eroded and deposited

¶ Upper section of the field site with avalanche barriers, cable car cables and upper hut (Photo: SLF). The field site is accessible via the following facilities: "Hof Dischma" car park on Dischmastrasse [...] path; additional network of paths within the field site Buildings ¶ Stillbergalp in winter (Photo: SLF). Two huts (cabins) were built in the immediate vicinity of the field site: The lower hut is situated [...] afforestation study. Climate measurement station ¶ Stillberg climate station within the field site (Photo: SLF). The automatic climate station at Stillberg (2,090 m) has been in operation since 1975. The climate

Permafrost ¶ Head: Dr. Marcia Phillips The SLF Permafrost research group investigates the long-term evolution of permafrost in mountain regions, focusing on ground temperatures, ice-/ water contents, and [...] y. We provide maps and guidelines to support practitioners’ planning processes and decisions. Our data is available via the Swiss Permafrost Monitoring Network PERMOS , which is co-hosted in our group [...] University of Fribourg. We cover one of the six core topics of the CERC research centre , which is part of SLF. Brief insight into our research activities ¶ Monitoring ¶ Climate and topography primarily determine

Research SLF provides essential information about the state of the permafrost and helps to understand the complex interactions between the ground surface and the underlying substrate. Nine of SLF’s boreholes [...] immediately visible, there are some landforms that can indicate its presence, such as rock glaciers. Data from boreholes ¶ Since 1996, we have drilled boreholes at thirty permafrost sites in the Swiss Alps

footage shows how warm air is moved by wind from above the open ground on the left into the area above the snowpack. (Video: Michael Haugeneder / SLF) The image taken by the infrared camera shows how warm [...] the left to the area above the snow cover. SLF scientist Michael Haugeneder explains how the measurement works in the video here . (Video: Michael Haugeneder / SLF) How long would it have to snow to make [...] Lack of snow in winter 2022/23: FAQ ¶ For weeks, the WSL Institute for Snow and Avalanche Research (SLF) has been receiving a lot of enquiries about the current lack of snow, its impacts this summer and

date back around 50 years, but some go back more than a century. These measurements and decades of data management today provide a valuable basis for resolving many practical questions, such as determining [...] studies are very important. Snowpack responds to climate change Thanks to the long-term measurement data, we have been able to identify some clear trends. The last 30 years have seen very low levels of snow [...] forecasts based on a combination of climatic and snowpack modelling. We combine a variety of past weather data and climate warming scenarios to simulate the future snowpack in the Alpine region. If climate-damaging

of feedbacks with the climate we can expect from these changes. The scientists worked with existing data from the Swiss National Forest Inventory LFI and the land use statistics. But they studied also processes [...] protective forest thereby increases. Furthermore, there are less avalanches in dense forests than in open forests. As a matter of fact, the protective effect of many forests has improved – although not always [...] conditions are favorable for old-snow avalanches. Since 1971, i.e., since there exist reliable measuring data, these two typical situations of forest avalanches have decreased. However, since snow conditions

the soil? Then it's worth taking a look at SNOWPACK. The SNOWPACK model applies meteorological input data to describe the layering of the snowpack and the snow microstructure. Developed primarily for avalanche [...] create models for snowpack changes. Fig. 1: Principal physical processes described by SNOWPACK. Image: SLF SNOWPACK is based on a Lagrangian finite element implementation and solves the non-stationary heat [...] exchange by the snowpack. Fig. 2. The SNOWPACK column, consisting of soil, snow and vegetation. Image: SLF archive Structure of physical modelling SNOWPACK is based on the modelling of a one-dimensional so

a thousand buildings in Switzerland and around a hundred people lost their lives. In response, the SLF stepped up its research in the field of avalanche protection and avalanche protection measures were [...] Switzerland has a very high level of avalanche protection. Fortunately, fatalities in settlements or on open transportation routes are very rare nowadays. Topics ¶ Artificial avalanche triggering Artificial

storm also made the ice unsafe, opening up a number of cracks and crevasses. Ice landscape from above and below In spite of this, we've been able to collect plenty of data over the past two weeks. This is [...] measure, dismantle, move on... The TLS measurements are somewhat less comfortable as we're out in the open air all day. The reflectors, scanner, stand and generator are packed on a sledge. For the measurements

Dr. Michael Lehning Contents ¶ Topics Projects Staff The group in charge of snow processes at the SLF is operated in collaboration with the chair for Cryosphere Sciences at the EPFL in the framework of [...] model "SNOWPACK" simulates the development of the snow cover during the winter based on meteorological data. Boundary-layer dynamics We investigate the interaction between the snow cover and the atmosphere

| Logbook Author ¶ David Wagner With the research vessel Polarstern moored to a suitable ice floe, SLF researcher David Wagner and his colleagues start to explore their surroundings and install measuring [...] could dig regular snow profiles in the months ahead. We were soon busy installing power lines and data cables and setting up larger power distributors at the main locations. We also performed the first [...] triggered further ice movements – which indeed were so strong this time that a huge diagonal rift opened up temporarily in the floe. Unfortunately, three of our main installations were situated on the other

role: in winter, the avalanche warning service at the WSL Institute for Snow and Avalanche Research SLF publishes the avalanche bulletin . for Switzerland twice a day, while our hydrologists are involved [...] forest fire, and determine the consequences for ecosystems such as protection forests. We make our data, findings and products available to the public and safety authorities on internet platforms, as apps [...] processes and assess the influence of protective measures. Avalanche bulletin and snow situation The SLF provides continuous information on the current avalanche and snow situation during the winter season

drones ¶ Brief insight into our research activities ¶ Drones in the high mountains ¶ The use of UAVs opens new perspectives to natural hazard research in alpine terrain. Geodata from poorly accessible locations [...] alpine areas ¶ The Alpine Remote Sensing group investigates mass movements by combining remote sensing data acquired from different platforms (terrestrial, airborne, spaceborne) and sensors (radar, multispectral

weather and snow transport data in East Antarctica. We are thereby able, for the first time, to record the snow transporting processes which take place in the Antarctic winter. The data can be used to estimate [...] transport. Measurements in the wind tunnel ¶ Fig. 2: Taking measurements in the wind tunnel. Image: SLF archive In two wind tunnels we are analysing the transport and sedimentation of snow in controlled