During the 2009 Christmas season, several particularly serious avalanche accidents occurred, this time affecting northern Italy in particular. Here, 7 winter sports enthusiasts, including four mountain rescuers, lost their lives within a few days. Anyone who followed the avalanche reports and warnings from the avalanche warning services before and after Christmas would have realized that we were dealing with a very dangerous avalanche situation.
Experienced freeriders and ski tourers who deal with snow and avalanche science feared early on that the extremely cold period in December, in combination with the often very thin snow cover and simultaneous radiant weather, had greatly transformed the snow cover. But is the cause of the accidents actually to be found in the often weakened snowpack structure caused by the conversion? And how did this precarious avalanche situation come about? We wanted to find out from Patrick Nairz, deputy head of the Tyrolean avalanche warning service.
Questions to Patrick Nairz about snowpack development and avalanche danger
PowderGuide: Almost all avalanche warning services have recently issued urgent warnings about the unstable snowpack and the high triggering readiness of avalanches. Can you briefly explain to us how this came about?
Patrick Nairz: The situation that arose from 20.12.2009 onwards had to do with the long cold spell already mentioned. The snow cover built up massively at that time. The result: Loose, angular crystals, surface frost on the snow surface. In addition, wild snow [editor's note: very light, fine, unbound powder snow] often fell from the high fog-like cloud cover. This has a similarly negative effect as surface frost after snowing / blowing in.
PowderGuide: Will the situation ease from now on or do you expect the avalanche situation to remain very tense?
Patrick Nairz: The situation has eased in the meantime. This is also clearly shown by our snowpack surveys, which we have carried out almost daily throughout Tyrol over the past few weeks. More and more fresh drift snow accumulations have to be observed at the moment. Nevertheless: Above about 2000m there are still enough "nests" where the old snow cover can still be disturbed by winter sports enthusiasts, especially in transition areas from little to much snow. The steeper the slope, the more likely it is that an avalanche will be triggered.
PowderGuide: How do you assess the further development, are we facing a dangerous winter with a correspondingly high number of avalanche victims?
Patrick Nairz: This question cannot be answered at the moment. It depends 100% on how the weather develops - and we (fortunately) don't know that.
PowderGuide: Do you have any tips on how freeriders or ski tourers should behave in order to protect the weak snow cover as much as possible or not overload it, so that avalanches are not triggered in the first place?
Patrick Nairz: Freeriders now have the advantage that everything is always skied down immediately in the off-piste area. This naturally has a positive effect on the further development of the snowpack. The leeway in the off-piste area is therefore significantly greater than in classic, less frequented and used touring terrain. My tips: If in doubt, do without! Listen to your instincts! Avoid impulse loads and remember: the steeper the slope, the greater the risk of triggering an avalanche. Standard measures such as relief distances are a prerequisite!
PowderGuide: What is most likely to stabilize the snowpack? Is the current rain up to medium and high altitudes rather good or rather bad for snowpack stability?
Patrick Nairz: The rain on December 25th didn't have such a good effect in the short term, of course, but the subsequent drop in temperature had a very positive effect. In the meantime, however, we can also observe some angular crystals at the interface of the snow layer that formed at that time, which - depending on the temperature development - could possibly serve as a sliding surface for slab avalanches (altitude range 1900-2300 m).
PowderGuide: Patrick, thank you very much for taking the time to answer our questions.
Overview of avalanche accidents during the Christmas week '09
Tête de Balme (Switzerland), 21.12.09: A snowboarder died in an avalanche outside the marked piste in the Tête de Balme region of Valais. The victim was a 25-year-old Frenchman.
Verbier (Switzerland), 23.12.09: On the Col des Mines near Verbier, a skier left the marked pistes this morning and was caught in an avalanche. Thanks to an avalanche search device, he was located and rescued by his companion under half a meter of snow. He was flown by helicopter to Sion Hospital for a check-up. During this rescue operation, the rescue services witnessed a second avalanche on the Col de Creblet. An off-piste skier was also caught in an avalanche there, but was not buried under the masses of snow, according to the police. He was injured and also taken to hospital by helicopter.
Thyon (Switzerland), 23.12.09: In the afternoon, three people left the marked pistes in the Thyon ski region and were caught in an avalanche. They were able to free themselves without injury. Further avalanches were reported to the Valais cantonal police during the course of the day. However, no people were injured.
Anzere (Switzerland), 27.12.09: An avalanche fell on a marked ski slope in the ski resort of Anzere in Lower Valais on Sunday. One person was rescued, another snow sports enthusiast is still being sought.
Graubünden (Switzerland), 27.12.09: Two avalanches also occurred in the canton of Graubünden on Sunday afternoon. According to the cantonal police, one of them was triggered by two ski tourers on Piz Avat in the municipality of Sumvitg. They were able to free themselves under their own power and alert Rega. They were flown to hospital. One of the two suffered a foot fracture, the other rib injuries.
On Piz Nair above St. Moritz, several skiers triggered an avalanche away from the marked and secured pistes. According to the police, they were lucky to avoid the masses of snow. As one of the seven or so skiers was missing his companion, a search operation was launched involving Rega, SAC Bernina and the Piz Nair and Marguns SOS teams. After some time, however, the missing man came forward. He had already descended to the valley.
Pitztal (Austria), 21.12.09: Two ski tourers recovered dead from avalanche. Two ski tourers from Germany who had been missing since Monday could only be rescued dead on St. Stephen's Day in Hinteres Pitztal in the Tyrolean district of Imst. They were discovered by mountain rescuers near the Braunschweiger Hütte in the municipality of St. Leonhard several meters deep under masses of snow.
Sölden (Austria), 25.12.09: Minibus caught and buried by avalanche
A minibus was caught and buried by an avalanche above Sölden on Friday afternoon. The three occupants were able to free themselves and did not suffer any life-threatening injuries.
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Hochgurgl (Austria), 26.12.09: A young German skier was caught by an avalanche about 20 meters wide in the open ski area in Hochgurgl on Saturday afternoon. The skier was completely buried, but was fortunately rescued alive.
South Tyrol/Trentino (Italy), 26.12.09: Seven people were killed by avalanches in South Tyrol and Trentino on Saturday. A 14-year-old snowboarder was buried by an avalanche. Four mountain rescuers died while searching for a pair of tourists.
On the Pordoljoch (sic! Editor's note: Pordoijoch) in Trentino - close to the border with South Tyrol - four mountain rescuers who were trying to find two missing tourists in the dark died on Saturday evening. The search team was caught and swept away by an avalanche at an altitude of more than 2,000 meters in the Lasties Valley.
A 14-year-old German snowboarder was killed on Saturday in Sulden in South Tyrol when he was on his way with two companions and was caught and buried by the masses of snow. The two others were rescued alive by the rescue services, one of them had suffered back injuries.
Schnalstal Valley (Italy), 26.12.09: Late on Saturday morning, a man was buried by an avalanche in the Schnalstal Valley ski area. The 31-year-old from Truden was on the glacier lake piste with his snow groomer at around 11.30 a.m. and wanted to repair a broken wire rope when the avalanche occurred. Colleagues had observed the accident and immediately informed the rescue services.
More accidents off the slopes
Wengen (Switzerland), 21.12.09: The death of Myles Robinson is the topic of conversation in the ski resort of Wengen. The Englishman disappeared without a trace on the night of December 22nd after a visit to a bar. On Monday evening, a private search party found the man dead at the foot of the Steinhaltefluh, just before Lauterbrunnen.
Bivio (Switzerland), 26.12.09: A skier from the canton of Zurich had a fatal accident on Saturday afternoon in Bivio GR on the Julier Pass. The man caught his skis on a frozen snowdrift and fell headfirst into the deep snow. He was unable to free himself from this situation under his own power.
