Lotte Arai Resort Mountain
The landform the resort sits on: the shape of the hill beyond the pistes, how steep it gets, and where it stands among the mountains on JapowDB.
Broadly one hillside, leaning to the east.
Where this vertical sits among the mountains on JapowDB
951 m, more than 30 of the 34 mountains on JapowDB.
The mountain
大毛無山 (Ōgenashi-yama)
- Landform
- Ōgenashi-yama is not a volcano, which makes it unusual among the mountains around Myoko. It is a block of Neogene sea floor raised on the boundary between Myoko and Joetsu, part of the Kubiki range, and the andesite volcanoes stand to its south. The lifts reach 1,279 m and the summit is 1,429 m, so about 150 m of the mountain is left above the top station. Its east face carries a cliff called Zendana, over 30 m high and running for some 600 m, where the covering beds have been stripped off and the sandstone underneath is bare. It stays black through the winter while the ground around it is under snow.
- Rock
- The whole hill is one rock: marine sandstone and mudstone in alternating beds, laid down on a sea floor in the Miocene. Samples at the top of the lift-served ground, at mid-mountain and near the base come back identical, so all 944 m of vertical stands on a single soft sedimentary pile. Soft rock wears down evenly, and the east side of the mountain is one broad face, and the runs on it all look the same way. The exception is Zendana, where the covering beds have gone and the sandstone below is left as bare cliff.
From published sources, checked by hand · 2026-09-23
That ground is outside the ski area. It is not patrolled.
Measured
01
Which way it faces
Faces east.
Most of the mapped runs fall away toward the east.
02
How steep it gets
The steepest quarter of the runs faces north-east, a different way from the mountain overall.
Its steepest pitch measures 37.2°.
Its steepest tenth is steeper than 27 of the 34 mountains here that carry pitch data.
21.5° the steepest tenth of runs
03
How varied it is
Its runs range from 6.4° to 26.4°.
Half of them are gentler than 12.3°. Each mark is one run.
That spread is wider than 27 of the 34 mountains here that carry pitch data.
04
What grows on it
Mostly deciduous: broadleaf woods and larch. They stand bare through the winter, so you can see a long way into them.
Read off the national vegetation survey (2024 edition), from fieldwork in 2017 and 2003.
The forest on this mountain, in detail