Triglav Glacier

During the last Ice Age, the Bohinj Glacier extended across the Vrata Valley and through the region of Dežela all the way to the gates of Radovljica. This large glacier experienced crisis periods during the warmer interglacial phases. The present-day Triglav Glacier is not a remnant of that ancient glacier. The Triglav Glacier (traditionally called Green Snow due to the bluish-green color of its ice) was once the largest glacier in Slovenia. Its remnants lie on the northeastern slope below the summit of Triglav.

In the 16th century, the extent of the Triglav Glacier was smaller than in 1957, as can be inferred from conditions in the High Tauern, where gold and silver were mined in tunnels near the glacier margins in the 16th century, only to be re-covered by advancing ice.

In Slovenia, the Institute of Geography at the Slovenian Academy of Sciences and Arts (SAZU) began systematic monitoring of glacier conditions in 1946. The only glaciers in Slovenia (and then Yugoslavia) were three: the Triglav Glacier, the glacier below Mount Skuta, and the Skedenj Glacier above Krnica on the northern side of Prisojnik.

Due to elevation, only Triglav and the Triglav Glacier are suitable for observing the boundary of permanent snow. This boundary is not fixed—it shifts over time and even from year to year. In 1955, researchers discovered dead ice beneath moraine debris on the Triglav Glacier. They concluded that the glacier had once extended to that point roughly eighty years earlier (Gams).

Based on mapping the glacier’s edge, its area was determined to be 46.9 hectares, which aligns with the first recorded measurement from 1888, citing 45.9 hectares (Richter). Between 1946 and 1952, the glacier’s area fluctuated between 13 and 16 hectares (Gams).

It was found that glaciers absorb up to 80% of the heat required for melting through insolation, which can be direct or indirect. Comparative studies of glacier fluctuations and climate variations in the Eastern Alps revealed: “Glaciers retreat primarily in years with clear, sunny, and warm summers, and advance in years with cloudy, humid, and cool summers.” (Gams)

The growth or decline in glacier thickness depends on the balance between snowfall and melt. For Triglav, the boundary of permanent snow was estimated at an elevation of 2700 meters.

Due to warm climate conditions, the Triglav Glacier likely did not exist during the last third of the Middle Ages. By the mid-19th century, however, it covered around 40 hectares. This period, when Eastern Alpine glaciers were at their largest, is known as the Little Ice Age.

“In the colder modern era known as the Little Ice Age, when Eastern Alpine glaciers reached their maximum length around the mid-19th century, the Triglav Glacier measured slightly over 40 hectares in the 1870s.” (Gams)

From the mid-19th century to the 1880s, winter precipitation increased, then declined until the mid-20th century, and began rising again thereafter. In the second half of the 20th century, summer temperatures also rose, and Kredarica began receiving most of its precipitation in summer. October became drier. Although winter temperatures also increased, the average from 1961 to 1990 remained well below freezing.

A major factor in the glacier’s decline was the reduction in October precipitation. This month had previously contributed to snow accumulation, but began providing less and less. Increased summer rainfall, on the other hand, accelerated ice melt.

The condition of the middle and lower glacier is most affected by average summer temperature (which rose by 1.6 °C between 1992 and 1994) and the number of sunshine hours (which increased by 11% in the same period). It was precisely the temperature during the melting season and the amount of snowfall during the accumulation season that led to rapid retreat after 1983 and complete disintegration after 1991.

Thus, Slovenians lost our only glacier, and its disappearance is difficult to accept. Yet there is still hope for its recovery. This would require several consecutive years with abundant snowfall during the accumulation season and cool, cloudy summers during the melting season.

Go to Triglav Glacier