Three days ago
Avalanche Bulletin Friday, 12.03.2010, at 07:30
Fresh snowdrift & poor snow layering cause considerable avalanche danger widespread
Avalanche Danger
The avalanche danger in Tyrol’s backcountry touring regions remains by and large dependent on altitude: below about 2000 m the danger level is moderate, above that altitude it is considerable widespread. Avalanche prone locations are to be found primarily on wind loaded and steep slopes in southwestern to northern to eastern expositions. Freshly formed and older snowdrift accumulations are poorly bonded with the old snowpack and can usually be triggered by minimum additional loading, even by the weight of a single backcountry skier or freerider. Backcountry tours in outlying terrain away from secured ski runs require extensive experience in spotting and evaluating avalanche perils. The situation on heavily frequented, standard backcountry tours is more favourable.
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Snow Layering
Over the last 24 hours there has been a few centimeters of snowfall in North Tyrol. The new fallen snow has not had any significant effect on the avalanche situation, but often covers and conceals older danger zones, making them exceedingly difficult to recognize in open terrain. All in all, the snow layering is unfavourable this winter: on the one hand, both snow depths and snow firmness are highly irregular even across small surface areas. On the other, the fundament of the snowpack consists largely of faceted, unbonded snow crystals. Atop this loosely packed, trigger sensitive base, layers of snowdrift of highly varied depth have been deposited which can still be triggered as avalanches with relative ease.
Alpine Weather Forecast (ZAMG-Weather Service Innsbruck)
Weather: a northwesterly current is supplying moderately cold, intermittently moist air masses to the northern flank of the Alps. In southern regions, a northerly foehn wind is blowing. Temperatures will correspond to the season only as of the middle of next week. Mountain weather today: final local snow showers will come to an end this morning. The clouds will disperse sometime during the morning hours and it will turn sunny, by midday even in the eastern part of the Lower Inn Valley. A few residual clouds will cling to the mountain flanks. Light to moderate northerly winds. Temperature at 2000 m: minus 12 to minus 8 degrees; at 3000 m: minus 16 to minus 12 degrees.
Short Term Development
No significant change in the avalanche situation.
[Author: Rudi Mair]
[Translated by Jeffrey McCabe]
Two days ago
Avalanche Bulletin Saturday, 13.03.2010, at 07:30
Avalanche danger depends on altitude: below 2200 m moderate, above 2200 m considerable widespread
Avalanche Danger
The avalanche danger in Tyrol’s backcountry touring regions is by and large contingent on altitude: below about 2200 m it is generally moderate, above that altitude considerable widespread. The major hazard stems from snowdrift accumulations which have been deposited on an old snowpack which is highly prone to triggering. These snowdrift masses are themselves often covered and concealed by small amounts of loosely packed new fallen snow, making them very difficult to recognize in open terrain. Avalanche prone locations are to be found primarily on southwest to north to southeast facing wind loaded and steep slopes, where avalanches can still be triggered by minimum additional loading, even by the weight of a single backcountry skier or freerider. Solar radiation and the daytime warming cycle have helped to consolidate the uppermost layers of the snowpack on sun bathed slopes.
Snow Layering
The characteristics of the snowpack vary greatly this winter, even across small surface areas. This is true of the snow depth as well as the structure of the surface layers and their stability. The overriding hallmark, however, remains the widespread unfavourable fundament, consisting largely of faceted, unbonded snow crystals, which are then covered by snowdrift accumulations of varying depth. The bonding of these snowdrift masses to the snow layers lying beneath them is often poor, making avalanches relatively easy to trigger.
Alpine Weather Forecast (ZAMG-Weather Service Innsbruck)
Weather: a northwesterly air current is bringing moist, cool air masses in deep layers to the northern flank of the Alps. At the beginning of next week, a powerful system of precipitation will arrive, as of mid-week milder Atlantic air will make itself felt. Mountain weather today: on the Main Alpine Ridge and south thereof, a generally sunny day is expected. The further north and east you go, the denser the clouds become, which are moving in from the north. Particularly between the Karwendel, Kitzbühel Alps and Wilder Kaiser, light snowfall is possible over the course of the day. Temperature at 2000 m: minus 11 to minus 7 degrees; at 3000 m: minus 13 degrees. Moderate northwesterly winds at high altitudes and in the eastern mountain ranges.
Short Term Development
Avalanche danger remains dependent on altitude: below 2200 m moderate; above that, considerable.
[Author: Rudi Mair]
[Translated by Jeffrey McCabe]
Yesterday
Avalanche Bulletin Sunday, 14.03.2010, at 07:30
Avalanche danger is generally moderate, above 2200 m considerable in some regions
Avalanche Danger
The avalanche danger in Tyrol’s backcountry touring regions has receded to moderate in general, although above approximately 2200 m it is still considerable regionally. Avalanche prone locations are to be found on southwest to north to southeast facing wind loaded and steep slopes. In particular freshly formed and older snowdrift accumulations can be released as avalanches widespread even by minimum additional loading, including the weight of a single backcountry skier or snowboarder. Extreme caution is urged on steep, seldom frequented or unfrequented touring routes. Heavily frequented routes are more favourable.
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Snow Layering
The hallmark of the snowpack this winter is that it is highly varied, even across small surface areas: both snow depth and snow firmness shift drastically from meter to meter, as does the snowpack structure at the surface. The fundament is weak widespread, consisting predominantly of faceted and thus, loosely packed snow crystals; atop this trigger sensitive base lie snowdrift accumulations of varying depths, which can still be easily triggered as avalanches. On steeper, sun bathed slopes, the surface softens up during the late morning, depending on solar radiation.
Alpine Weather Forecast (ZAMG-Weather Service Innsbruck)
Weather: clouds from Bavaria are still streaming against the northern flank of the Alps. This coming week begins with two bouts of precipitation from the northwest. As of mid-week, the air current will shift to westerly, and warmer Atlantic air masses will follow in its wake. Mountain weather today: south of the Main Alpine Ridge it is sunny. Even in the Stubai and Ötztal Alps it should be sunny for longer periods today, before the clouds begin to dominate. In the western Northern Alps and on the Main Alpine Ridge east of the Brenner, intermittently sunny, then clouds will move in from the north. In the Northern Alps east of the Karwendel, often heavily overcast and intermittent light snowfall. Temperature at 2000 m: minus 10 to minus 6 degrees; at 3000 m: minus 12 degrees. Moderate northwesterly to westerly winds.
Short Term Development
Avalanche danger will increase with snowfall.
[Author: Rudi Mair]
[Translated by Jeffrey McCabe]
Today
Avalanche Bulletin Monday, 15.03.2010, at 07:30
Above approximately 2200 m, still considerable danger regionally, escalating due to snowfall
Avalanche Danger
In the northern regions from Ausserfern to the Kitzbühel Alps, moderate danger now prevails, below 1700 m the danger level is low. Further to the south, at least above approximately 2200 m, the danger level is persistently considerable, below that altitude it is moderate, at low altitudes it is low. The snowfall which is forecast will increase the avalanche danger somewhat, particularly in northern regions. Caution is still urged towards relatively unfrequented, steep terrain, especially above the treeline, where primarily on very steep west-northwest to north to east-northeast facing slopes slab avalanches can be released even by minimum additional loading. Above approximately 2400 m, this is the case in other expositions as well. Below about 2400 m, avalanches on east-northeast to south to west-northwest facing slopes can ordinarily be triggered only by large additional loading. In northern regions, particularly on north facing slopes, caution is urged on very steep slopes. Over the course of the day, new snowdrift accumulations will form which, particularly in steep areas adjacent to ridge lines, are hazardous. Due to highly variable conditions even across relatively small surface areas, it is difficult even for experienced backcountry skiers and freeriders to spot and assess the perils. Evaluation of hazards is simplest in heavily frequented terrain, where quite favourable conditions now reign.
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Snow Layering
The snowpack at low altitudes is compact. At intermediate altitudes, it is also compact, except on very steep north facing slopes. With increasing altitude, layers of depth hoar become more and move evident in some regions, surrounded by hardened melt freeze crusts and wind crusts. In places with shallow snow, fractures deep inside the old snowpack are quite possible, which is just what occurred in the fatal avalanche accident yesterday below the Nockspitze. At higher altitudes, the wind crusts become more frequent, beneath which a great deal of depth hoar lurks, particularly in exposed places. The snowpack’s proneness to triggering is still demonstrated by its settling noises, which can be provoked in flat and moderately steep terrain above the treeline which has until now been unused by backcountry skiers and freeriders.
Alpine Weather Forecast (ZAMG-Weather Service Innsbruck)
Wintery weather conditions in North Tyrol’s mountains. On the northern flank of the Alps, 10 to 20 cm of snowfall is possible by this evening; on the Main Alpine Ridge maximum 10 cm. Lots of fog and brisk winds. On the southern flank of the Alps, windy but sunny. Temperature at 2000 m: minus 7 degrees; at 3000 m: minus 14 degrees. Moderate to strong northwesterly winds.
Short Term Development
Increasing avalanche danger due to snowfall and wind.
[Author: Patrick Nairz]
[Translated by Jeffrey McCabe]