Swiss glacier watcher warns recent heat wave threatens severe melt again, after record 2022

A top glacier watcher has warned that a warm early summer combined with a heat wave last week may have caused severe glacier melt in Switzerland, threatening to make 2023 its second-worst year for ice loss after a record thaw last year.

A top glacier watcher has warned that a warm early summer combined with a heat wave last week may have caused severe glacier melt in Switzerland, threatening to make 2023 its second-worst year for ice loss after a record thaw last year.

Matthias Huss of the GLAMOS glacier monitoring center said full data won't be in until late September and a precipitous drop in temperatures and high-altitude snowfall in recent days could help stem any more damage.

But early signs based on readings from five sites and modeling results across Switzerland suggest considerable damage may already be done.

"We can definitely say that we had very high melting in Switzerland and in Europe in general because the temperatures, they were extremely high for a long time -- a more than one week heat wave," Huss said in an interview this week.

Swiss meteorologists reported last week that the zero-degree Celsius level had risen to its highest altitude since recordings on it in Switzerland began nearly 70 years ago -- meaning that all of the Alpine country's mountains faced temperatures above freezing.

The late-summer heat wave was particularly harmful to glaciers this year because high temperatures earlier in the summer had already melted nearly all of the protective snow cover, which meant that "almost all glacier ice was kind of naked," Huss said.

A blanket of white snow cover has a crucial effect in protecting glaciers by reflecting energy from sunlight back upward, a process known as the albedo effect.