Suretta Sud Glacier - Servizio Glaciologico Lombardo

Ablation season ( June 1 –September 30, 2008)
The beginning of the 2008 summer was positive
for the glaciers, with the first half of June
relatively chilly and snowy above 3000 m,
with isolated snow episodes even at 2200 m
a.s.l.. Starting in the second half of June the
tropical high, the so-called “camel”, set in and
rose the temperature, seriously damaging the
snow cover which started to melt down very
rapidly. On the 26th of June the temperature
reached 16,3 °C at the 2509 m a.s.l. of Bivacco
Corti, the highest value for the season.
The anticyclone produced temperatures exceeding
the average value for the season (+
2,6 °C over the mean values for the period
1961-1990 at Sils). Temperatures remained
high also in July, despite a number of storms
causing snowy precipitations above 3600 m
a.s.l.. This phase ended with the flood event
of the 11th -14th, when 138,6 mm of rain fell
at Andalo (Lower Valtellina). The Lake Como
overflowed again at Como after a few years
and the Adda River exceeded the warning
threshold for some days. Snow fell only
above 3100-3300 m a.s.l., with 30-40 cm of
accumulations. Thanks to a warm second
half, July ended with temperatures exceed-
- 11 -
ing the mean value, though showing a lower
deviation than the previous month of June (+
0,7 °C at Sils). July 2008 was the rainiest July
since 1987, fortunately without inflicting the
same damages to the Valtellina area. August,
though perceived by most people as a chilly
month, was probably the worst month for
the glaciers of Lombardy. The rain fell even
on the highest glaciers, washing away some
of the residual snow cover and speeding up
the ablation. Moist weather and cloud cover
kept the minimum temperature above 0 °C for
several days, preventing the melting and refreezing
process so important for the survival
of the snow cover on glacial apparatuses.
Overall, the anomaly (+ 1,6 °C) was important
enough to cause the almost complete melting
of the residual snow covering the Lombardy
glaciers. The few accumulations, mostly due
to avalanches, suffered an additional blow in
the first ten days of a hot and dry September.
On the other hand, from the 13th of September
onward, the month was characterized by
a series of abundant snowfalls at relatively
low altitudes for the season. These were responsible
for the slowing down, or the final
Tab. 3: Precipitation and temperature values during the 2007/2008 ablation season. In order to allow a homogeneous
comparison among the different stations, the mean values refer to the period 1988/89 –2005/2006. “Integral”
means that the average temperature is calculated by adding each recorded value (data acquisition interval:
5’) and the total is divided by the number of readings. The other temperatures have been calculated with the
“arithmetic” method: i.e. (average of daily maximum temperatures + average of daily minimum temperatures) / 2.
Weather Station
Precipitations in mm
June - September, 2008
(Deviations from the mean
values)
Temperatures in °C
June - September, 2008
(Deviations from the mean
values)
Bivacco Corti - 2509 m/s.l.m. - + 6,8° (integral + 6,8°)
Sils/Maria - 1798 m/s.l.m. 572,7 (+ 129,2 mm ; + 29,1 %) + 10,1° (+ 0,2°)
S.Antonio di Valfurva - 1360 m/s.l.m. 473,2 (+ 99,8 mm ; + 21,0 %) + 13,4° (+ 0,1°)
Sondrio - 290 m/s.l.m. 498,9 (+ 100,6 mm ; + 26,3 %) + 20,8° (- 1,0°)
Andalo Valtellino - 220 m/s.l.m. 666,1 (+ 151,5 mm ; + 29,4 %) + 20,4°
Massimeno (TN) - 860 m/s.l.m. 421,9 (+ 37,0 mm ; + 9,6 %) + 16,7° (- 0,3°)
snow-meteo report