App Maps Climbing Congestion on Japan’s Peaks

By Mayumi Oshige, Takaaki Suzuki / Yomiuri Shimbun Staff Writers

20:00 JST, June 5, 2023

The climbing season has begun in earnest, and with the easing of the COVID-19 pandemic, the number of people keen to traipse up and down the nation’s various peaks is expected to surge.

But overly busy mountain trails can give rise to dangerous situations, prompting The Yomiuri Shimbun to ask the Fukuoka-based operator of the Yamap mountaineering app to analyze GPS data and flag possible congestion points.

“There was a long line of climbers both in front of and behind me, spaced out by a meter or two,” said a Tokyo-based office worker recalling a pre-pandemic visit to Mt. Tsubakuro in Nagano Prefecture in August 2019. The 47-year-old said 30-40 people were waiting in line to use the public restroom at the trailhead. He also recalled an “ant-like” procession of climbers traversing the path to the Fujimi Bench rest point, situated roughly halfway up the 2,763-meter peak.

“It was impossible to climb at my own pace, which made it difficult,” he said.

Mt. Tsubakuro, which is known as an “introductory” elevation for people keen to later take on more challenging peaks in the Northern Japan Alps, attracts a large number of climbers.

Based on data from the Yamap app operator related to busy climbing points across the nation over the past year, the Fujimi Bench area of Mt. Tsubakuro saw the most congestion, logging 61 very busy occasions.

A mountain guide in Matsumoto, Nagano Prefecture, said the mountain trails around that point are narrow and when climbers traveling in opposite directions pass each other, those on one side have to wait while the others pass along the trail, causing congestion.

“Some climbers don’t want to wait and stray from the climbing trails, which can be dangerous,” the guide said.

Mt. Fuji key points

According to the Japanese Alpine Club, this is the first time for GPS data to be used to analyze congestion on mountain trails around the nation.

Based on Yamap users’ GPS data, the operator defined “congested” as being when it took 30 or more climbers five seconds or more to travel 1 meter within a one-hour period, excluding those taking a break. The survey flagged congested points at 90 locations around the country, from Hokkaido to Kagoshima prefectures.

Many of the congestion points were rocky or narrow or had attractive views featuring alluring scenery or flowers.

Of the “top 10” congested points, five were concentrated along the Mt. Fuji trail that runs from the Yoshida trailhead on the Yamanashi Prefecture side of the mountain, which is often used by climbers from the Tokyo side. Most of the congestion points on the 3,776-meter-high peak were located near the summit.

Mt. Fuji is expected to attract a large number of climbers this year, as it celebrates its 10th year as a UNESCO World Heritage site. The prefectural government intends to ease congestion through such measures as shortening the operation hours of a toll road that leads to the fifth station.

Other congestion points in the top 10 ranking include locations in Mt. Mizugaki in Yamanashi Prefecture, Mt. Akadake in the Yatsugatake Mountains, Mt. Nantai in Okunikko, and Mt. Yarigatake in the Northern Japan Alps.

Research necessary

According to the Tokyo-based Japan Productivity Center, Japan had around 6.5 million active climbers in 2019, but this figure dropped during the pandemic to 4.6 million in 2020 and 4.4 million in 2021. However, these numbers are picking up again, as the pandemic subsides.

Hitoshi Onodera, executive director of the Japan Mountaineering & Sport Climbing Association, said, “Congestion can lead to people deviating from their plans and cause difficulties in responding to sudden health problems if toilets and mountain lodges become overcrowded.”

Daisuke Saito, a data scientist at Yamap Inc. who analyzed the data, said: “There were some unexpected results, such as congestion occurring not only at Mt. Fuji, but various other less well-known mountain ranges, too. We hope this data will be utilized to help formulate plans for mountaineering, similar to researching where traffic jams are likely to occur.”