The recent deaths of 10 hikers in Hokkaido's Taisetsu mountain range serve as a tragic reminder that even summer mountaineering can be perilous. Hiking in bad weather, the 10 — all in their 50s and 60s — died from hypothermia. One was on a guided tour of 2,052-meter Mount Biei. The other nine were climbing 2,141-meter Mount Tomuraushi, with eight on a guided tour and one doing a solo ascent.

Guided mountain tours are popular these days, especially with the middle-aged and elderly. But participants must keep in mind that the presence of guides does not necessarily ensure that the tour is safe. In times of trouble, hikers must ultimately rely on their own judgment and strength. Before deciding to take part in a mountain tour, people should determine whether they are in sufficiently good health and possess the necessary strength for such an event, and whether the tour includes arrangements for emergency evacuation in the event of bad weather. They must also make sure they have the proper gear. Even in summertime, both warm and waterproof clothing is essential equipment when climbing mountains.

The tour group in Mount Tomuraushi was composed of 15 climbers and four guides. They were hit by strong rain and winds. One climber after another fell behind due to the bad weather and the group became scattered. When a person is hit by rains and strong winds, water evaporates and steals away precious body heat. When a person's temperature falls below 30 degrees C, he or she is in real danger of death. Children as well as middle-aged and elderly people, in particular, have difficulty maintaining normal body temperature in harsh conditions.

In the Tomuraushi tour, organized by a Tokyo-based company, the participants were scheduled to traverse a distance of more than 40 km from Mount Asahi to Mount Tomuraushi in two nights and three days. But this schedule was apparently based on the assumption that the weather would be good.

Competition may be forcing tour companies to increase pressure on their guides to make sure tours stay on schedule regardless of the weather. The police should determine whether the Tokyo firm took sufficient precautions for the possibility of bad weather and whether the guides performed their duties properly.