Believe It or Not, Japan Has Glaciers, Too! Experts Explain the Risk of a Major Collapse as the “10 Glaciers” in the Northern Alps Melt

Wait, there are glaciers in Japan? What’s the risk of collapse?  

A mudslide occurred in Nepal in August. One theory suggests that as the glacier melted, water seeped into the bedrock, weakening it and causing it to collapse.Glacier collapses are currently occurring all over the world; last year, a glacier in the Swiss Alps collapsed, causing a major disaster that completely wiped out an entire village.

In fact, there are 10 glaciers in Japan, located around Mount Tateyama and Hakuba. These are situated right next to popular hiking areas that attract many visitors every year. Currently, there are over 270,000 glaciers worldwide, and glacier collapses are occurring one after another in various regions. Given this situation, what would happen if Japan’s glaciers were to collapse, as they have in Switzerland or Nepal? Could a situation arise where hikers are caught in the collapse and villages at the base of the mountains are engulfed?

“I don’t think there’s any cause for concern,”

This is the confident assertion of Kotaro Fukui of the Tateyama Caldera Sabo Museum, who studies glaciers.

“Japan’s glaciers are very small in scale. Some glaciers in the Alps reach lengths of 20 km, cover areas of about 100 km²—larger than the area within the Yamanote Line loop—and are hundreds of meters thick.In contrast, Japan’s largest glacier—the Sannomado Glacier on Mt. Tsurugi—is 1.6 km long, covers an area of 0.13 km², and is 60 to 70 meters thick, making it completely incomparable.”  

This glacier flows into the Kurobe River, but even if it were to melt, it would only cause the river’s water level to rise slightly. Moreover, since the glacier is located deep in the mountains, it is unthinkable that it would affect any settlements.The only exception is the Kuranosuke Glacier on Mount Tateyama, which is located near a hiking trail; however, at 350 meters long, it is one of the smallest glaciers in Japan. Accidents like those in Switzerland or Nepal are unlikely to occur here.”

“Unique Glaciers” Born of Heavy Snowfall

Reports indicate that 20 percent of Switzerland’s glaciers have been lost over the past five years, and it is said that the Lewis Glacier on Mount Kenya has lost 90 percent of its volume over the past 80 years or so. What is the situation with Japan’s glaciers?

“While they have been shrinking in recent years, their area has decreased by only about 10 to 20 percent over the past 60 years, so the current rate of retreat is significantly slower than that of glaciers worldwide,”

Mr. Fukui explains that the reason for this is that Japan’s glaciers are unique.

“Most of the world’s glaciers are located in cold regions at higher latitudes or higher elevations than Japan. Japan is situated in a warm, mid-latitude region and has no mountains reaching 4,000 meters. For that reason, it was once thought that Japan had no glaciers. Yet the reason glaciers do form here is that this area is one of the world’s heaviest snowfall regions.”

Every year, snow begins to fall around November in the Northern Alps region, triggering avalanches and causing snow to accumulate on the glaciers.In the rugged valleys of the Northern Alps where glaciers exist, that snow reaches a depth of about 20 meters by early spring, and since it takes four to five months to melt, the surface of the glacier does not become visible until around October. Eventually, snow falls again, avalanches occur, and snow accumulates on the glacier. This is why the rate of retreat is slow.

Signs of Global Warming Revealed by Glaciers

It wasn’t that long ago that we first realized glaciers even existed in Japan.

A glacier, as the name suggests, is a river of ice. As the ice thickens, its weight causes it to flow downward. If it does not flow, it cannot be recognized as a “glacier.” Thick ice is essential for flow, but it was believed that, with the exception of a single snowfield, the ice in Japan’s mountains was no more than about 15 meters thick at its deepest.

However, starting in 2009, a team led by Mr. Fukui from the Tateyama Caldera Landslide Prevention Museum conducted surveys using ice radar and surveying GPS. They discovered that the Sannomado area of Mt. Tsurugi has ice 60 to 70 meters thick, and that Gozenzawa also has ice 30 meters thick—and that these glaciers are moving.

“The reason we conduct glacier surveys is that there are almost no locations at elevations of 1,500 meters or higher where long-term meteorological observations are being made, so we don’t know whether global warming is occurring in the Northern Alps. Therefore, we are investigating whether global warming is taking place by analyzing changes in the glaciers.”  

Temperatures in Switzerland are rising at twice the global rate, which is believed to be the cause of glacial retreat, but

“In Japan—and particularly in the Northern Alps—we cannot yet definitively state that global warming is definitely occurring at elevations above 1,500 meters. However, we don’t know what will happen in the future. There is a possibility that they could disappear entirely. While it is said that Swiss glaciers are melting due to global warming, what will happen in Japan?I want to continue my research for 10 or 20 years, observing the glaciers while monitoring environmental changes.”

▼Kotaro Fukui: Assistant Curator, Curatorial Division, Tateyama Caldera Sabo Museum ( Public Interest Incorporated Foundation). Ph.D. in Science. Specializes in research on glaciers and permafrost. He previously served as an overwintering member of the Japanese Antarctic Research Expedition. He is currently conducting surveys of the glaciers in the Tateyama region.“I want to gain a deep understanding of Japan’s glaciers,” he says.