GENEVA, April 8 (Xinhua) -- In the Swiss Alps, permafrost temperatures were the highest in 20 years between September 2019 and October 2020, the Swiss Permafrost Monitoring Network (PERMOS) said in a report released on Thursday.
Permafrost is ground that remains frozen for two or more consecutive years. It is found under about five percent of Switzerland's surface.
The hydrological year 2019-2020 was "the warmest on record in Switzerland," PERMOS said. Air temperatures were around one degree Celsius higher than average during winter.
PERMOS said that in September 2020 permafrost surface temperatures "were close to or even above the previous records set in 2003, 2015 and 2018."
A warm spring and two summer heatwaves in 2020 also had a disproportionately negative effect on the Swiss permafrost, whose surface layer was "very warm" and where the temperature readings at a depth of ten and 20 meters also "exceeded the previous record values," the report said.
"In 2020, rock glaciers accelerated significantly with an average increase in velocity of 21 percent compared to 2019. Like surface and permafrost temperatures, rock glacier velocities in 2020 were close to or even above the previous record set in 2015," PERMOS said. Enditem