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Short winter marked by little snowfall and few avalanche victims

Review of winter 2016/2017

News Release, 03.05.2017

Winter 2016/17 was characterised by warm temperatures and extremely little snowfall. Many places had continuous snow cover only for a very brief period. Seven people were killed in avalanches – significantly fewer than average over a 20-year period.

Ende Dezember und kaum Schnee
At the end of December there was very little snow at the Grindel measuring site, at around 2000 m (Grindelwald, canton Bern). Photo: D. Balmer, 31.12.2016
 
Gefahrenzeichen wie Risse in der Schneedecke waren im Januar und Februar 2017 typisch
Danger signs, such as cracks in the snowpack, alongside whumpfing sounds and remotely triggered avalanches were typical of the conditions that prevailed in January and February 2017. Photo: M. Cambrini, 8.1.2017, Muttental, canton Uri
 
Nach dem schneearmen Frühwinter war der Schneedeckenaufbau im Januar verbreitet schwach
After an early winter phase with little snow, the snowpack in January was weakly bonded over widespread areas, as illustrated by this snow profile above St. Martin in Val d'Hérens, canton Valais. 40 cm of fresh and drifted snow were deposited on an old snowpack with a crust and, below that, large cup-shaped crystals. Photo: P. Gaspoz, 15.1.2017
 
Lawine am Schafgrind bei Davos
Remotely triggered avalanche on the Schafgrind near Davos, unleashed by backcountry skiers, which fractured at the weak base of the snowpack. Photo: SLF/A. Bodisch, 19.1.2017
 
Ablagerungen grosser Lawinen am Grimselpass

Debris deposited by very large avalanches on the Grimsel Pass (Lochlaui, Mäderlaui and Gschitzlaui avalanche paths in Guttannen, canton Bern), which triggered naturally on 9 March 2017. Photo: A. Henzen, 10.3.2017

Numerous ski resorts were delighted by the large quantities of snow that fell in the mountains starting in mid-November. Their excitement was of short duration, however, since foehn winds which followed in its wake quickly melted the white blanket. December was the driest month, with the least amount of snow, since measuring commenced. Many winter sport resorts reported a green Christmas for the second year in succession. The coveted snowfall finally arrived in January – but in much smaller quantities than a year earlier. Nevertheless, the lowest temperatures in 30 years in the Swiss plateau region ensured that the snow cover lasted for several weeks, even at low altitudes.

Despite the January snowfall, winter 2016/17 ranked among the poorest in snow ever recorded. Substantial quantities of snow did not arrive until the beginning of March. But since the entire month was far too warm, the snows quickly melted and many measuring stations saw the shortest period of continuous snow cover in their history. In Ulrichen in Obergoms, for example, continuous snow cover lasted for just 86 days, which corresponds to little more than one-half (56 %) of the long-term average (156 days). Wintery conditions returned in mid-April with copious snowfall and low temperatures.

March was the only month with exceptional avalanche activity and numerous large natural releases

The lack of snow was reflected in the winter's avalanche danger forecasts. Danger level 1 (low) was forecast by the SLF almost twice as frequently as the average over the last ten years. The higher danger levels 2 (moderate), 3 (considerable) and 4 (high) were published five times less frequently than usual. Weak layers formed in the shallow snowpack in the early winter, and in January and February backcountry skiers and freeriders could easily release avalanches in some places. The fairly substantial snowfall at the beginning of March gave rise to numerous large-sized natural avalanches, some of which damaged or completely destroyed buildings, forests or transportation routes, including numerous chalets in Vallon de Van in canton Valais.

Exceptionally small number of avalanche victims

By the end of April seven people had lost their lives in avalanches this winter. This figure is around 65 % lower than the 20-year average of 20 deaths recorded by this date. The 20-year average for the whole hydrological year, which runs until 30 September, stands at 23 avalanche victims. Of this winter's victims, five were backcountry ski tourers and two were freeriders. For the first time in nine winters, none of the fatal avalanches claimed more than one life – this factor probably contributed to the small number of victims. Some were presumably saved simply by good fortune, given that 148 people were caught in avalanches, which is also below average, but only 20 % lower. That means that relative to the number of accidents, avalanches killed far fewer people than usual.

Avalanche bulletins

The avalanche bulletin will continue to appear daily until further notice. It is available at www.slf.ch and with the SLF White Risk app. Subscribe to our RSS feed and text messaging service if you wish to be notified of the publication of an avalanche bulletin in the early and late winter and during the summer. (To order the service, text START SLF SOMMER to 9234. To unsubscribe, text STOP SLF SOMMER to 9234. Texts cost CHF 0.20.) An Alpine weather report in German is also available from MeteoSwiss at www.meteoswiss.ch, by phone on 0900 162 138 (CHF 1.20/min.), or with the MeteoSwiss app.

Further information

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Contacts

Christine Pielmeier, Avalanche Warning Service, WSL Institute for Snow and Avalanche Research SLF, Tel. +41 81 4170125, pielmeier@slf.ch

Julia Wessels, Communications, WSL Institute for Snow and Avalanche Research SLF, Tel. +41 81 4170286, wessels@slf.ch