‘Comes in like a lion...’ No sign of that this April. Thus far it is revealing only its very best side: unseasonably warm and dry. The period of extreme dryness will persist, briefly interrupted next week by a weak cold front. Subsequently, high-pressure weather conditions will return, according to current forecasts of ZAMG Weather Service.
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| Spring makes its entry. Innsbruck (photo: 05.04.2020) |
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| Fine weather, snow depths gradually receding (sublimating more than melting). This stems from the dry air masses around 5 April. Thereafter moisture in the atmosphere has been on the rise. Daytime variations in temperature of the snowpack surface are also flatter, i.e. nocturnal outgoing longwave radiation and re-firming of the snowpack have lessened. |
The snowpack: predominantly stable
During clear, star-studded nights, a melt-freeeze crust formed on sunny slopes, capable of bearing loads, which frequently softened up only superficially during the morning depending on altitude. On shady slopes at high altitudes, the snow often remained powdery despite higher temperatures. Where there was wind influence, a corn snow mirror formed on sunny slopes: a shining, thin crusty veil stretched over the surface.
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| Corn snow mirror on Rosskogel, Stubai Alps (photo: 05.04.2020) |
Hardly any avalanches observed
Avalanche activity was very limited. In isolated cases, small slides of gliding snow were observed; on 8 and 9 April on shady slopes between 2500 and 2800 m, small loose-snow avalanche releases, stemming primarily from heightened air moisture, secondarily from higher temperatures. The loosely-packed snow became superficially moist and was weakened somewhat. Thus, avalanche danger was ‘low’ all week, with only minor daytime increases to ‘moderate.’
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| View of Northern Massif near Innsbruck. A ‘sleepy’ snowpack with isolated glide cracks and small slides in rocky terrain (photo: 05.04.2020) |
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| For comparison, a photo from 9 April. Despite moister air masses (around 3000 m) no new avalanches were observed. |
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| Small loose-snow avalanches on shady slope in Griesskogel Group (photo;: 09.04.2020) |
No major change on the horizon
As regards avalanche danger outlook, a continuous moistening of the snowpack on shady slopes seems to be the most important factor, particularly above 2500 m. Due to current weather forecasts, this is not expected in the immediate future.
Otherwise worthy of note
Dryness of the air leads not only to decelerated melting at high altitudes, but also to heightened danger of forest fires.
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| Swift intervention by the fire department was able to prevent the worst in Halltal. (photo: 08.04.2020 taken in Mils) |
A glance at streams and brooks awakes the impression that there isn’t much water flowing. But measurement data shows that water levels are average, typical for this juncture of the season.
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| Inn River flow at Innsbruck |
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| Water level of the Inn (photo: 09.04.2020) |
HAPPY EASTER!
