Ice trees can be seen in winter at the Zao Onsen Ski Area. At that time, the hills of the Ou Mountains are covered with snow. Many ice trees, standing at twice the height of a man, appear like 'shrimp tails'. Skiers on the slopes glide between the ice trees.

Zao is the only place in the world where ice trees can be seen. Certain conditions are necessary for them to appear:
*a place where aiophyllous coniferous trees, such as pines, grow;
*strong seasonal winds of a low-temperature that blow from the same direction so that, as cloud droplets strike the trees' branches and leaves, they freeze immediately, in a process called 'ice coating';
*the snowfall should not be too much nor too little.

From late January to late February, the ice trees are illuminated, producing a fantastic atmosphere.