Gwytherin to Oerfa°
5855.5 m · net rise 148.0 m · total ascent 258.6 m · overall 2.5% · confidence: good · Gwytherin · Clwyd
Shape: stepped — 57% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 269 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 the OS road network, surface models and map tags, 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.
° The name is provisional: this climb is not yet matched to a documented name, so it was named from nearby map places. There is no evidence of local usage — (auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (53.1242, -3.7104)'). Corrections welcome.
Gradient ladder what do windows mean?
| Window | Maximum | Located at | |
|---|---|---|---|
| 2 m (diagnostic) | ≈39% | 1071–1073 m | under overhead cover terrain reads 69.1% at 302–304 m across a structure — excluded |
| 3 m (diagnostic) | ≈36% | 1071–1074 m | under overhead cover terrain reads 63.0% at 302–305 m across a structure — excluded |
| 5 m | ≈29% | 1070–1075 m | under overhead cover terrain reads 37.7% at 302–307 m across a structure — excluded |
| 10 m | ≈24% | 274–284 m | under overhead cover terrain reads 26.1% at 295–305 m across a structure — excluded |
| 20 m | ≈22.4% | 247–267 m | under overhead cover terrain reads 25.1% at 285–305 m across a structure — excluded |
| 25 m | ≈21.9% | 242–267 m | under overhead cover terrain reads 24.7% at 280–305 m across a structure — excluded |
| 50 m | ≈20.7% | 238–288 m | under overhead cover terrain reads 22.3% at 255–305 m across a structure — excluded |
| 100 m | ≈19.3% | 350–450 m | under overhead cover terrain reads 19.4% at 209–309 m across a structure — excluded |
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.
Ridden it, or know better? Submit data for this climb no account needed
© OpenStreetMap contributors · topo tiles © OpenTopoMap (CC-BY-SA) · vector tiles OpenFreeMap
Profile
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:27700",
"elevation_resolution_m": 1.0,
"elevation_tiles": [
"data/cache/wales/dtm_1m/wg_del_11_283358_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_283359_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_283360_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_283361_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_284358_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_284359_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_284360_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_284361_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_285358_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_285359_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_285360_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_285361_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_286358_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_286359_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_286360_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_286361_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_287358_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_287359_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_287360_20210302dtm.tif",
"data/cache/wales/dtm_1m/wg_del_11_287361_20210302dtm.tif"
],
"calculated_at": "2026-08-12T00:50:22+00:00",
"road_source": "OpenStreetMap (local PBF extract)",
"road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
"osm_pbf_path": "data/cache/pbf/wales-2026-08-11.osm.pbf",
"osm_snapshot": "2026-08-10T20:21:40Z",
"elevation_provider": "Welsh Government",
"elevation_dataset": "Welsh Government LiDAR 1m DTM (2020-2023)",
"elevation_licence": "Open Government Licence v3 \u2014 \u00a9 Crown copyright Welsh Government",
"elevation_catalogue_layer": "geonode:welsh_government_lidar_tile_catalogue_2020_2023",
"elevation_tile_ids": [
"wg_del_11_283358_20210302dtm.tif",
"wg_del_11_283359_20210302dtm.tif",
"wg_del_11_283360_20210302dtm.tif",
"wg_del_11_283361_20210302dtm.tif",
"wg_del_11_284358_20210302dtm.tif",
"wg_del_11_284359_20210302dtm.tif",
"wg_del_11_284360_20210302dtm.tif",
"wg_del_11_284361_20210302dtm.tif",
"wg_del_11_285358_20210302dtm.tif",
"wg_del_11_285359_20210302dtm.tif",
"wg_del_11_285360_20210302dtm.tif",
"wg_del_11_285361_20210302dtm.tif",
"wg_del_11_286358_20210302dtm.tif",
"wg_del_11_286359_20210302dtm.tif",
"wg_del_11_286360_20210302dtm.tif",
"wg_del_11_286361_20210302dtm.tif",
"wg_del_11_287358_20210302dtm.tif",
"wg_del_11_287359_20210302dtm.tif",
"wg_del_11_287360_20210302dtm.tif",
"wg_del_11_287361_20210302dtm.tif"
],
"elevation_capture_dates": [
"02-03-2021"
],
"climb_origin": "discovered",
"notes": "Coarse pass: max 18.1% over 200 m (Terrain 50), gain 121.2 m over 4841 m way. EXTENDED by graph walk: +1 segment(s) at base, +3 at top (stop: base=no_descending_continuation, top=no_ascending_continuation; min_avg=2.0%). Review before adopting.",
"naming_note": "auto-named from gazetteer (hypothesis, unreviewed); discovered as 'Discovered lane (53.1242, -3.7104)'"
}