Thornton Creek

Getting There

Drive SR-20 to 11 miles east of Marblemount and turn north onto Thornton Lakes Road. If running the entire canyon, leave a car at the bottom of Thornton Lakes Road near SR-20. Continue driving up the road to a bridge that crosses Thornton Creek. If running the canyon to this point and not continuing downstream, leave a car at the bridge. Continue up Thornton Lakes Road to the final switchback before the road straightens out. Park here and follow the trail up to the drop-in.

Approach

Follow a faint use trail uphill, paralleling the creek, to 1,200 ft and drop into the creek. For a shorter day, drop in at 1,130 ft, which shortens the descent by four rappels.

Descent

This canyon has multiple multi-stage rappels, some off of natural anchors and others off of bolted anchors. Many rappels require traversing potholes on rope, or end in a pothole that must be traversed to access the next rappel anchor. Be aware that in high flows, these potholes may contain hydraulics or risk pushing canyoneers over the pour-over. Only experienced teams should descend this canyon in conditions that exceed moderate—review the "waterflow" indicators on  ropewiki.com.

Exit

Exit at the bridge, or follow the creek below the final rappel until it passes under Highway 20. Follow a path on the north side of Highway 20 back to your car.

EQUIPMENT

Standard canyoning gear including webbing, a wrench and replacement quick links. 

TRIP PROFILE

• Rappels: 10-15
• Longest Rappel: 200 feet
• Approach: 0.25 mile
• Exit: 0.1 mile
• Time: 5-8 hours total

NOTES

• This canyon is rated v4a4III at moderate water levels (late August & September), and v4a5 in early to mid-season.
• It is possible to run upper sections of the creek, which are largely jumps and slides, but route has not yet been documented. 
• For more information and recent trip reports from the community, visit the Thornton Creek listing at ropewiki.

information for leaders

Courses, paid clinics, staff-led programs, and course field trips require a Commercial Use Authorization. The Park typically accepts applications for 2-year CUAs  through mid-March each year, and CUA's are activity-specific. Please contact info@mountaineers.org if you would like to apply for a CUA for a field trip or paid clinic for an activity we do not already have a CUA for. Please follow all Mountaineers group guidelines when leading trips or courses in North Cascades National Park. 

Notes:

• Leaders are responsible for securing backcountry permits or other required permits even if  we have a CUA.
• Leaders must have all relevant CUAs with them in paper or electronic copy to show Parks Staff as requested. 
• All Hiking course field trips or paid clinics must have a First aid and CPR certified leader. Current (non-expired) certificates must be uploaded to the park web portal by Mountaineers staff prior to the trip
• All mountaineering field trips or paid clinics must have a WFR-certified leader and a leader with documented climbing certifications (an AMGA certification OR Mountaineers climb leader with a recent resume of training and experience). Both qualifications must be uploaded to the park web portal by Mountaineers staff prior to the trip

View list of current North Cascades CUAs

• Suitable Activities: Canyoning
• Seasons: July, August, September
• Weather: View weather forecast

• Difficulty: Intermediate Canyon
• Length: 0.5 mi

• Land Manager: North Cascades National Park
  Ross Lake National Recreation Area
• Parking Permit Required: None
• Recommended Party Size: 8
• Maximum Party Size: 12
• Maximum Route/Place Capacity: 12