Keep your winter diary
The presence of snow on the ground for a longer or shorter period of time is one of the main characteristics of the mountains. It shapes life through its insulating power in winter and through the large water reserve it provides, which is available in spring. However, the duration of the snow cover and its height have already decreased significantly since the 1970s due to the rise in temperature.
The snow is receding in duration and abundance, especially at low and medium altitudes. Since the 1970s, the duration of snow cover between 1100m and 2500m has been reduced by 5 weeks in the Northern Alps. In terms of snow depth, the maximum snow depth at the Cignana station at 2150m in the Italian Aosta Valley has fallen by 50% compared to the period 1961-1990. This represents a decline of more than 10% per decade. At the Col de Porte (1325m altitude, Chartreuse massif), a decrease of 37.7 cm in the thickness of the average snow cover was observed between the periods 1960-1990 and 1990-2020.
From a species perspective, the scientific questions are: What survival for species adapted to the presence of snow: those that change colour during the year to better camouflage themselves (ptarmigan, hare, ermine), those whose survival depends on the insulating effect of the snow (black grouse, voles, common ragweed, etc.), those adapted to late melting (snowbed plants), and those physically adapted to the presence of snow (ptarmigan and its "snowshoes", chamois and their interdigital membranes)? How does the earlier availability of water due to the decline in snow cover influence the phenology of trees and amphibians? How does snow melting too early impact species through lower water availability in summer? Overall, which species are benefiting and which are suffering from the decline in snow cover?
In order to answer these questions, it is necessary to know the evolution of the snow cover locally. From the valley floor to the peaks, the "snow cover" programme invites you to follow the snow height day by day and season by season. This method is complementary to what can be obtained from satellites or cameras.
Target audience
Region
Season
Implementation time
1 minute per day during the winter period
Naturalist difficulty
- Novice
- Naturalist
Involvement
The programme requires regular follow-up on your part
Access to study site
Equipment
a graduated snow pole
The protocol
1 Identify
In an open, flat area near your home (you can participate regardless of the altitude of your location), stick a measuring pole marked with 5cm graduations into the ground (starting with 0 at the ground).
2 Observe
As soon as the first snow falls, go to your pole and crouch down to observe the height of the snow cover. Round up if necessary (i.e. if the height is approximately between 10 and 15 cm, write 15cm).
Repeat this process every morning at the same time until the end of winter. If it is more convenient for you, print out the field sheet and fill it in by hand. Once the season is over, enter your measurements into SPOT and send them to us. Be careful, when there is no snow, note 0 cm because it is also an observation!
3 Send
Log into your SPOT account and go to the Contribute page, then the Snow cover section. If this is your first measurement, click on register a new tracking spot and then locate your spot on the map. Then click on add a measure, fill in the various fields and validate to finish.
Practical advice
Ideally, you should start noting the snow cover as soon as the season begins. However, if you have a gap of a few days in your measurements, it doesn't matter. Continue for the next few days, this data will still be useful to us.
If you have been using the field sheet to record the daily snow cover, please feel free to use the multiple entry option to send us your observations. This will allow you to quickly enter several observations at once.
Toolbox
