Spring skiing in places like Zermatt and Saas-Fee could become a thing of the past if the long-term trend discovered by Swiss researchers continues.
The joint study, whose results were published in the Climatic Change journal last week, was carried out by the University of Neuchâtel along with the Federal institute for research on forests, snow and the countryside (WSL) and the Institute for the study of snow and avalanches (SLF).
Until now such studies have mainly focused on winter only, but this one analyzed snow coverage across autumn and spring too, using data from 11 Meteo Suisse weather stations of various altitudes over the period 1970 to 2015.
The study found that all the resorts – both at low and high altitude – saw a shortening of the duration of annual snow cover over the 45-year period.
Overall, snow arrived 12 days later and disappeared 25 days earlier in 2015 than in 1970 – a decrease of 37 snow days at an average of 8.9 days a decade.
The maximum snow depth also reduced by 25 percent over the years, researchers found. And the day on which this maximum is achieved arrives 28 days earlier now than 45 years ago.
The early melting of snow in spring contributed most to the shortening of the season, said the WSL, with the later arrival of snow in autumn being a lesser factor.
Speaking to The Local, the project's lead researcher, WSL climatologist Professor Martine Rebetez, said while people already knew snow coverage was decreasing at lower altitudes (around 1,500m), “we were surprised to see that it has changed exactly the same at higher elevation”.
The all-season approach showed that, while higher elevation resorts have lower temperatures in winter and therefore retain their snow, during autumn and spring the decline in snow coverage is the same as in lower altitude resorts.
Analyzing the 45-year period of data shows a long-term trend linked to rising temperatures caused by climate change, said Rebetez.
Switzerland's snow cover may therefore continue to drop in the future.
“What we have seen is that [snow decline] is perfectly coupled with the temperature increase. So it will totally depend on how much temperatures will increase in the coming decades. As we are not doing anything at this point to reduce climate change then the snow [decrease] will just follow the temperature increase,” said Rebetez.
The situation could have a serious impact on Switzerland, not least on ski tourism.
While lower Swiss ski resorts have been observing snow decrease “for decades”, the study shows for the first time that higher resorts are also affected, said Rebetez.
“For those at higher elevation, places like Zermatt or Saas-Fee, they are in a good position now because they are high enough, but it's important that they know that even at higher elevation the process is going on. It will just be a question of some more decades for them to be concerned as well,” Rebetez told The Local.
Lack of snow melt could also lead to water shortages in Switzerland, she said.
“In some places we might run short of water at the end of the summer, for instance. So there might be consequences on some summers if there a dry period, then we might get into more trouble than we did before when we had more snow and more glaciers.”
Switzerland has enjoyed a particularly warm summer this year, with September carrying on the trend. On Thursday meteorologists said it was the third hottest September since records began, Swiss media reported.