Mount Zaō

Zaō Mountains
Zaō Mountains
蔵王連峰
	The Zaō Mountains as seen from the Shiroishi River, an Abukuma River tributary, at the cherry blossom season
Highest point
Elevation	1,841 m (6,040 ft)
Listing	Mountains of Japan; Volcanoes of Japan;
Coordinates	38°08′38″N 140°26′24″E / 38.144°N 140.44°E
Geography
	Zaō Mountains Location on Honshu Zaō Mountains Zaō Mountains (Japan)
Country	Japan
Island	Honshu
Prefectures	Yamagata; Miyagi;
Geology
Mountain type	Complex volcano
Last eruption	May 1940

The Zaō Mountains (蔵王連峰, Zaō Renpō), commonly called Mount Zaō, are a complex cluster of stratovolcanoes on the border between Yamagata Prefecture and Miyagi Prefecture in Japan. The central volcano of the group includes several lava domes and a tuff cone, Goshiki-dake, which contains a crater lake named "Okama". Also known as the "Five Color Pond" (五色沼, goshiki numa) because it changes color depending on the weather, it lies in a crater formed by a volcanic eruption in the 1720s. The lake is 360 metres (1,200 ft) in diameter and 60 m (200 ft) deep, and is one of the main tourist attractions in the area.

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. Zaō is one of the 100 Famous Japanese Mountains.

Rotaria rotatoria^[3] and Pinnularia spp.^[4] are found in the acidic Okama Lake.^[5]