5 miles
Distance
1,543 ft
Climb
-300 ft
Descent
03:34:32
Avg time
Trail Supporters, Builders & Maintainers of Thunderbolt Mountain 65 Trail

Details

  • Riding Area
    Helena
    Helena, Montana
  • AKA
    Cottonwood Lake
  • Difficulty Rating
  • Trail Type
    Singletrack
  • Bike Type
    AM, XC, Fat
  • Trail Usage
    Multi-use
  • Direction
    Both Directions
  • Climb Difficulty
    Black Diamond
  • Physical Rating
    Hard
  • Season
    July-October
  • eBike Allowed
  • Global Ranking
    #17121 in Mountain Biking
  • Local Popularity
    5 in Mountain Biking [+]
    • 5 in Trail Running
    • 5 in Hiking
  • Land Manager
    USFS

The high elevation and thick timber make this trail one of the last in the region to shed snow, and drifts are common into late June. The trail to Cottonwood Lake is very popular with backcountry horsemen and horsewomen, so be alert, and make sure to park courteously, leaving room for horse trailers to turn around.

The trail to Cottonwood Lake is a moderate climb. From the lake, the trail climbs steeply to the top of Thunderbolt Mountain via the L.O. Connection. The junction is at the north end of the lake; if you carry on farther than that you have missed it and are headed into the Little Blackfoot watershed.

Access Info

Take the Bernice exit of I-90 (Exit 151) and follow the Boulder River Road (staying to the left). Stay on the Boulder River road to the Thunderbolt Creek road, which is directly opposite the Whitehouse Campground. The junction is a distinctive Y and is signed. The Thunderbolt Creek road ends at the trailhead.

Local Trail Association
More Stats for Thunderbolt Mountain Trail 65 bike trail
  • Altitude change
    1,243 ft
  • Altitude min
    6,393 ft
  • Altitude max
    7,636 ft
  • Altitude start
    6,393 ft
  • Altitude end
    7,636 ft
  • Grade
    4.902%
  • Grade max
    -28.786%
  • Grade min
    29.855%
  • Distance climb
    4 miles
  • Distance down
    5,057 ft
  • Distance flat
    1,179 ft
  • Avg time
    03:34:32
  • view trail stats
Status:
on Nov 1, 2017
Snow Covered
Avg: 4.5 (2 votes)

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Trail Conditions
  • Unknown
  • Snow Packed
  • Snow Covered
  • Freeze/thaw Cycle
  • Icy
  • Prevalent Mud
  • Wet
  • Variable
  • Dry
  • Very Dry
Trail Ridden Direction

Trailforks scans users ridelogs to determine the most popular direction each trail is ridden. A good flowing trail network will have most trails flowing in a single direction according to their intension.
The colour categories are based on what percentage of riders are riding a trail in its intended direction.

  • > 96%
  • > 90%
  • > 80%
  • > 70%
  • > 50%
  • < 50%
Trail Ridden Direction

The intendid direction a trail should be ridden.

  • Downhill Only
  • Downhill Primary
  • Both Directions
  • Uphill Primary
  • Uphill Only
  • One Direction

LEGEND
Trail Difficulties
  • Access Road/Trail
  • White
  • Green
  • Blue
  • Black
  • Double Black Diamond

Trail Report Status
  • Clear / Green
  • Minor Issue / Yellow
  • Significant Issue / Amber
  • Closed or Major Issue / Red

  • Land Owner Overlay
  • Wilderness (typically no bikes in USA)
  • BLM (public)
  • USFS (Wildlife sanctuaries darker than usfs)
  • State land
  • Indigenous
  • Military
Trail Conditions
  • Unknown
  • Snow Packed
  • Snow Covered
  • Freeze/thaw Cycle
  • Icy
  • Prevalent Mud
  • Wet
  • Variable
  • Dry
  • Very Dry
  • Map Markers
  • trail Trail Head
  • photo Photo
  • place Directory Listing
  • region Riding Area
  • TTF TTF
  • Parking Parking
  • Viewpoint Viewpoint
  • Information Information
  • Warning Warning
  • Directions Directions
  • Water Fountain/Source Water Fountain/Source
  • Sight Sight
  • Restrooms Restrooms
  • Gate Gate
  • Camping Camping
  • Trail Sign Trail Sign
  • Table or Bench Table or Bench
  • Other Other
      Directions to thunderbolt-mountain-trail-65 trailhead (46.283170, -112.473850)
      update trails status or condition

      Thunderbolt... Trail Reports

      datedescription
      Nov 1, 2017 @ 11:24am
      Nov 1, 2017
      reporter First real snowfall of 2017/18
      Sep 18, 2017 @ 1:00pm
      Sep 18, 2017
      Sep 16, 2017 @ 11:37am
      Sep 16, 2017
      reporter
      Aug 16, 2015 @ 11:17am
      Aug 16, 2015
      reporter
      May 31, 2015 @ 6:57am
      May 31, 2015
      As of Memorial Day weekend, there were significant drifts in the last half-mile below Cottonwood Lake, and solid snow above the lake.
      view all reports »

      Recent Ridelog Activity on Trail

      Past Week
      • 0 rides
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      6 Months
      • 0 rides
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      All
      • 2 rides
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      Photos

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      Routes with this trail

      titleratingdistance
      Thunderbolt Mountain
      13 miles

      Reviews / Comments

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      Use trail reports to comment on trail conditions.


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