Big Flat Road Climb
- long (17.3 km)
- 11 mi
- long (17.3 km)
- of climbing (1,031 m)
- 3,383 ft
- of climbing (1,031 m)
- average grade
- 5.9%
- average grade
- steepest 500 m
- 17%
- steepest 500 m
Elevation profile
From 709 ft at the bottom to 4,091 ft at the top. Grades are averaged over each half kilometre, from USGS elevation data, so short ramps can be steeper than they show.
Weather at the top of Big Flat Road this week
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Is it safe to bike up Big Flat Road?
We don't rate roads as safe or unsafe: crash counts can't say how risky a ride is, and roads people like to ride draw more riders, so they see more crashes. Most of this climb is a dirt road, and falls away from public roads rarely reach police reports. What the records show: no bike crashes were reported along the climb from 2021–2025.
Common questions about Big Flat Road
- How long and steep is the Big Flat Road climb?
- 11 miles (17.3 km) at 5.9% on average, climbing 3,383 ft (1,031 m) from 709 ft to 4,091 ft. The steepest half kilometre averages 17%. That makes it a Hors catégorie climb.
- Where does the climb start and finish?
- It starts at 41.69347, -123.90316, and tops out on the road at 41.79402, -123.86912.
- Is Big Flat Road paved?
- Mostly not: OpenStreetMap tags 100% of the climb as dirt or gravel. Dirt roads can be closed in fire season or after rain, so check with the land manager.
- How is the category worked out?
- From the climb's shape only: length in metres × average grade (%) of 16,000 or more for Cat 3, 32,000 for Cat 2, 64,000 for Cat 1 and 80,000 for HC. It describes how hard the climb is, not traffic or crashes.
- Where does this data come from?
- The climb is found from OpenStreetMap roads and USGS 3DEP elevation (every climb, not a list of famous ones). Access is from OpenStreetMap tags; gates and closures change, so obey posted signs. Crash counts are police reports in the California Crash Reporting System (CCRS) on data.ca.gov, counted where their map location is within 100 ft of the climb. The forecast is from the National Weather Service.
Other climbs nearby
- Gasquet-Orleans Road near Crescent CityHC · 7.0 mi at 8.8% · 3,228 ft · starts 1.0 mi away
- Ship Mountain RoadHC · dirt · 11 mi at 7.2% · 4,049 ft · starts 1.8 mi away
- Blue Ridge RoadCat 1 · dirt · 7.4 mi at 6.6% · 2,598 ft · starts 5.3 mi away
- Gasquet-Orleans Road near Crescent CityCat 2 · 6.4 mi at 4.4% · 1,486 ft · starts 7.1 mi away
- Bear Basin Road from 17N38Cat 1 · 7.7 mi at 6.1% · 2,484 ft · starts 9.6 mi away
- Bear Basin Road near Crescent CityCat 2 · 3.5 mi at 7.4% · 1,355 ft · starts 9.7 mi away
- RM300 RoadCat 3 · 1.1 mi at 9.8% · 545 ft · starts 11 mi away
- French Hill RoadHC · dirt · 14 mi at 5.2% · 3,766 ft · starts 12 mi away
Found from OpenStreetMap roads and USGS 3DEP elevation; ranked on shape only. Hors catégorie: length in metres × average grade (%) of 16,000 or more for Cat 3, 32,000 for Cat 2, 64,000 for Cat 1 and 80,000 for HC. It describes how hard the climb is, not traffic or crashes. Crashes: bike crashes reported within 100 ft of the climb, 2021–2025, from the California Crash Reporting System (CCRS), counted only where the report has map coordinates. Weather: National Weather Service. Access from OpenStreetMap tags; obey posted signs. How the data works.