Suretta Sud Glacier - Servizio Glaciologico Lombardo

Unusual April snowfalls
If it were not for April and May 2008, we would be reporting the worst situation ever for
the Lombardy glacialism. The meteorological pattern of April was characterized by Atlantic
stream, for the first time in this period of the year since 1998 (before that we have to
go back to 1989). Almost continuous south-westerly stream brought five precipitation episodes,
with snow limits always below the 2000 m a.s.l. level and sometimes close to the
1000 m mark: a much needed help for the glaciers that until the end of March were showing
an insufficient snow cover.
The first days of April were characterized by sunny days and, once again, by föhn wind
blowing intensely on the 2nd and 3rd April. Then, starting from the 6th of April, the turnaround:
a weak perturbation moved in over Lombardy, dropping 30-40 cm of snow above
1500 m a.s.l., accompanied by the first thunderstorm of the season in Lower Valtellina.
Beginning with the 9th, a period of perturbations set in and in about 10 days the mountain
scenery changed. On the 11th the snow fell until 1000 m; a significant accumulation that,
added to those of the previous days, reached 150 cm in the Orobic Alps and Valle Spluga
Sectors and 100 cm in the other areas. In the following days the level of instability remained
high and several storms contributed to further increase the snow cover. On the 14th another
Atlantic perturbation discharged 48 mm of rain at Gerola Alta (Orobic Alps), a level
that, at higher altitudes, is equivalent to almost 50 cm of snow. Other sectors showed more
scanty accumulations (about 20-30 cm). In the following days other weak perturbations
added an additional 20-30 cm over all the sectors. After the short break of the 16th, during
the days from the 17th to the 21st another Atlantic perturbation dropped 80-90 cm above
2000 m a.s.l. in the Orobic Sector and 50 cm elsewhere. In the following days, from the
22nd to the 28th, a high pressure set in, producing more stable conditions accompanied by
temperature values matching the average for the period. The consolidation process of the
snow cover benefitted from several freeze–thaw cycles, particularly on the southern slopes
below 3000 m a.s.l..
April played its last chances between the 29th and the 30th, ending on the 1st May with rain
and thunderstorms and a snow limit around 1800-2000 m a.s.l.. These events dropped an
additional 20-30 cm of snow, especially on the Rhaetian Alps (30 cm at the Maloja Pass).
April can be ranked among the best months for precipitation. Overall accumulations were
twice the average value for the month: 187,5 mm (+67%) at Andalo Valtellino (Orobic Sector);
215 mm (+105%) at Massimeno (Adamello Sector); 148,1 mm (+103%) at Sils/Maria
(Rhaetia); 106,9 mm (+106%) at S. Antonio Valfurva. A further proof that April was an exceptional
month: the combined snowfalls at Nevaio del Colombano (Monte Legnone - Orobic
Alps) were estimated at 308 cm. This is the best result of the last 5 years, the previous
record being 217 cm (November 2003).
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snow-meteo report