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Hurricane Mountain Road (east side)

3731.9 m · net rise 370.6 m · total ascent 375.1 m · overall 9.9% · evidence quality B (good) · Chatham · New Hampshire · share

Shape: sustained — 33% of the climbing sits in a quarter of the distance; longest continuous stretch at 10%+ is 464 m.

Not yet matched against documented climbs — the measurement stands on its own.

≈ Overhead cover (tree canopy or structures) spans 31% of this route — detected by comparing the surface model (DSM, treetops and rooftops) against the terrain model (DTM, bare ground). Under cover the bare-ground model is built from fewer laser returns, so metre-scale readings can wobble; maxima whose window sits in a covered zone are marked ≈ below — less certain — the flag does not say whether the true value is higher or lower. Longer windows average over more clean ground and are steadier.

Gradient ladder what do windows mean?

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 throughout, according to each state's road inventory.

Access: Held from rankings 2026-09-04 (D22 C, New England re-line): re-lined onto the bench the USGS point cloud finds, but under the traced line's 25 m maximum the cloud reads flank, ambiguous or absent — not a plain road bed — so neither the published nor the re-lined number is verified. Published number stands; off the rankings until a cross-section look.

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 USGS (public domain)

Profile

The 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:26919",
  "elevation_resolution_m": 1.0,
  "elevation_tiles": [
    "data/cache/usa/nh/USGS_1M_19_x33y489_NH_Umbagog_LiDAR_2016_D16.tif"
  ],
  "calculated_at": "2026-09-02T06:17:53+00:00",
  "road_source": "OpenStreetMap (local PBF extract)",
  "road_attribution": "\u00a9 OpenStreetMap contributors, ODbL",
  "osm_pbf_path": "data/cache/pbf/new-hampshire-260822.osm.pbf",
  "osm_snapshot": "2026-08-21T20:21:11Z",
  "run_id": "us-reline2-260902",
  "elevation_provider": "USGS 3DEP (The National Map)",
  "elevation_licence": "Public domain \u2014 USGS 3DEP 1 m DEM, courtesy of the U.S. Geological Survey",
  "elevation_dataset": "USGS 3DEP 1 m DEM, NH_Umbagog_LiDAR_2016_D16 (collected 2016)",
  "elevation_tile_ids": [
    "x33y489"
  ],
  "climb_origin": "named",
  "canopy_source": {
    "kind": "ept_corridor_max_return",
    "ept_source": "https://s3-us-west-2.amazonaws.com/usgs-lidar-public/NH_Umbagog_2016",
    "ept_crs": "EPSG:3857",
    "station_coverage": 0.998,
    "cell_ground_m": 1.0,
    "nodes_failed": 0
  },
  "license": "ODbL-1.0",
  "license_url": "https://howsteep.org/licensing"
}