| Zaō Mountains | |
| Other Name: | 蔵王連峰 |
| Elevation M: | 1841 |
| Elevation Ref: | [1] |
| Country: | Japan |
| Subdivision1 Type: | Island |
| Subdivision1: | Honshu |
| Subdivision2 Type: | Prefectures |
| Map: | Japan Tohoku#Japan |
| Coordinates: | 38.144°N 140.44°W |
| Type: | Complex volcano |
| Last Eruption: | May 1940 |
| Mapframe: | yes |
| Mapframe-Zoom: | 13 |
| Mapframe-Wikidata: | yes |
| Mapframe-Frame-Height: | 260 |
| Mapframe-Stroke-Width: | 1 |
| Fetchwikidata: | ALL |
The, 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 360m (1,180feet) in diameter and 60-1NaN-1 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[2] and Pinnularia spp.[3] are found in the acidic Okama Lake.[4]