The central volcano of the group includes several lava domes and a tuff cone, Goshiki-dake, which contains a crater lake named "Okama".

One striking feature of Zaō's famous ski resorts are the "frost-covered trees" (樹氷, juhyō) that appear in mid-winter.

Strong wind over the nearby lake fling water droplets which freeze against the trees and their branches, until near-horizontal icicles begin to form.

Falling snow settles on the ice formations, and the end result is a grotesque figure of a tree.

The effect of a full forest of such trees gives visitors a ghostly impression.