Hoshino Resorts Tomamu 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 south-east.
That steep ground sits high on the mountain.
Where this vertical sits among the mountains on JapowDB
585 m, more than 11 of the 34 mountains on JapowDB.
The mountain
トマム山 (Tomamu-yama)
- Landform
- Not a volcano, which is rare on JapowDB. Tomamu-yama is 1,239.1 m of accreted seafloor, and the runs are on its south side. The lifts stop about 60 m below the summit.
- Rock
- A Cretaceous accretionary complex: mixed rock scraped off the ocean floor as one plate slid under another. It is older than every volcano on JapowDB by a hundred million years, and it does not change anywhere on the hill.
From published sources, checked by hand · 2026-08-12
That ground is outside the ski area. It is not patrolled.
Measured
01
Which way it faces
Faces south-east.
Most of the mapped runs fall away toward the south-east.
02
How steep it gets
That steep ground sits high on the mountain.
The steepest quarter of the runs faces south, a different way from the mountain overall.
Its steepest pitch measures 27.3°.
Its steepest tenth is steeper than 24 of the 34 mountains here that carry pitch data.
20.5° the steepest tenth of runs
03
How varied it is
Its runs range from 4.5° to 23.6°.
Half of them are gentler than 11.0°. Each mark is one run.
That spread is wider than 22 of the 34 mountains here that carry pitch data.
04
What grows on it
This mountain has both, in separate patches. The deciduous stands drop their leaves and open up for the winter; the conifer stands stay closed.
Read off the national vegetation survey (2024 edition), from fieldwork in 2021.
The forest on this mountain, in detail