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Chemin du Bioley

3885.8 m · net rise 449.9 m · total ascent 454.8 m · overall 11.6% · evidence quality B (good) · Chamoson · Valais/Wallis · share

Shape: sustained — 30% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 822 m.

Found purely from mapping and LiDAR data, and not yet matched against books, race records or lists — it may be well known to locals under a name we've never heard. It was cross-checked against swisstopo’s swissTLM3D road model, OpenStreetMap and a second terrain model, but a discovery can still be an artifact of the terrain model or the map. Treat it as a well-evidenced hypothesis until someone has ridden it. If you know this road, tell us what you found — photographs, corrections and local knowledge all welcome; the map links below let you scout it first.

Gradient ladder what do windows mean?

may start earliermay continue beyond end Extent detection suggests reviewing where this climb starts/ends.

Map

Check this route yourself: Google Maps route via their router · Street View at the base where coverage exists · geojson.io our exact measured line · OpenTopoMap

This climb's data: OCL JSON — the full gradient ladder, quality flags and provenance in the OpenClimb Ladder format.

Surface: paved (4% unpaved), according to swisstopo's swissTLM3D road model: paved for the first 3,691 m; unpaved from 3,691 m to 3,844 m. The steepest 25 m lies on the paved part.

Access: Listed 2026-09-11 (Switzerland run 7): road audit — way 257559444: unnamed service way; way 257559444: service way, surface untagged. Never silently ranked or dropped (Peter, 2026-08-27). Also trimmed 2026-09-15 at the tail dog-leg (a driveway, Peter's ruling); steepest 25 m now 18.1 %.

Measured, not vetted. This page records what the laser record shows about the road's shape — nothing more. Nobody has necessarily ridden or inspected this road for the survey, and a page here is not a recommendation and no guarantee that the road is open, surfaced, rideable or safe. Gates, private sections, missing rights of way and hazards do not show up in elevation data. Check access and conditions on the ground and make your own judgment.

Ridden it, or know better? Submit data for this climb no account needed · Share this climb

Load the interactive map

Route colour = gradient over a 25 m window: <10% 10–20% 20–25% ≥25%

Topo (contours) Vector Aerial   © OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap · aerial imagery © swisstopo

Profile

The map, profile and gradient chart share one position — move your pointer over them and the marker follows. Colors are the gradient bands; the shaded span is the steepest 25 m. Any 25 m figure is good to about a point either way (why).

 

Measurement card

Provenance

{
  "analysis_version": "0.1.0",
  "sample_interval_m": 1.0,
  "interpolation": "bilinear",
  "smoothing": "none",
  "gradient_windows_m": [
    5.0,
    10.0,
    20.0,
    25.0,
    50.0,
    100.0
  ],
  "diagnostic_windows_m": [
    2.0,
    3.0
  ],
  "elevation_crs": "EPSG:2056",
  "elevation_resolution_m": 0.5,
  "elevation_tiles": [
    "data/cache/ch/swissalti3d_2024_2580-1116_0.5_2056_5728.tif",
    "data/cache/ch/swissalti3d_2024_2580-1117_0.5_2056_5728.tif",
    "data/cache/ch/swissalti3d_2024_2581-1116_0.5_2056_5728.tif",
    "data/cache/ch/swissalti3d_2024_2581-1117_0.5_2056_5728.tif",
    "data/cache/ch/swissalti3d_2024_2582-1116_0.5_2056_5728.tif",
    "data/cache/ch/swissalti3d_2024_2582-1117_0.5_2056_5728.tif"
  ],
  "calculated_at": "2026-09-15T21:34:48+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/switzerland-2026-09-10.osm.pbf",
  "osm_snapshot": "2026-09-09T20:21:20Z",
  "run_id": "retro-260915-dogleg-all",
  "elevation_provider": "swisstopo swissALTI3D",
  "elevation_licence": "swisstopo open government data (OGD): free use, attribution '\u00a9 swisstopo' \u2014 https://www.swisstopo.admin.ch/en/terms-and-conditions",
  "elevation_dataset": "swissALTI3D 0.5 m DTM (Federal Office of Topography swisstopo)",
  "elevation_tile_ids": [
    "2580-1116",
    "2580-1117",
    "2581-1116",
    "2581-1117",
    "2582-1116",
    "2582-1117"
  ],
  "climb_origin": "discovered",
  "canopy_check": "unavailable \u2014 no surface model (DSM or point cloud) registered for this coverage",
  "structure_own_ways": "none \u2014 the route carried no way list; own decks unmasked",
  "structure_mask_ranges_m": [
    [
      0.0,
      29.6
    ],
    [
      2.2,
      32.2
    ],
    [
      4.1,
      34.1
    ],
    [
      0.3,
      30.3
    ],
    [
      1.7,
      31.7
    ],
    [
      20.0,
      50.0
    ],
    [
      9.7,
      39.7
    ],
    [
      0.0,
      20.7
    ],
    [
      0.0,
      25.6
    ],
    [
      18.7,
      48.7
    ],
    [
      6.0,
      36.0
    ],
    [
      10.3,
      40.3
    ],
    [
      17.4,
      47.4
    ],
    [
      0.0,
      18.3
    ],
    [
      3.8,
      33.8
    ],
    [
      16.3,
      46.3
    ],
    [
      19.3,
      49.3
    ],
    [
      13.9,
      43.9
    ],
    [
      9.0,
      39.0
    ],
    [
      14.0,
      44.0
    ],
    [
      6.0,
      36.0
    ]
  ],
  "mask_basin_extension_m": 30.0,
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing"
}