As the winter ski season reaches its peak, the slopes of Japan’s major resorts are growing increasingly busy now that foreign tourism has resumed, and many may be looking to take their vacations a step further by going backcountry skiing.

But the death on Sunday of two men in Nagano Prefecture, including American world champion freestyle skier Kyle Smaine, was a tragic reminder of the risks involved in backcountry ski trips, even for expert skiiers.

Here is what you need to know about backcountry skiing in Japan: