Tinkham Peak - Route Beta Research (2026-01-29)

AI-Generated Research Document

This document was generated by an AI assistant and should be used as a starting point only.

YOU MUST:

• Verify all critical information from primary sources
• Use your own judgment and experience to assess conditions and risk
• Cross-reference with current trip reports and local conditions
• Understand that conditions change rapidly in the mountains

This is NOT a substitute for:

• Proper training and experience
• Current weather and avalanche forecasts
• Your own research and route planning
• Sound mountaineering judgment

The mountains are inherently dangerous. You are responsible for your own safety.

Overview

Tinkham Peak rises to 5,398 ft (1,645 m) with 677 ft (206 m) of prominence in the Cascade Range, King County, Washington. The peak is located at 47.349185, -121.454685 (Google Maps | USGS Topo). The standard route via Mirror Lake is a scramble rated Class 2 with brief Class 3 near the summit.

The route offers a scenic approach through old-growth forest, past Mirror and Cottonwood Lakes, before ascending a steep boot path to the rocky summit. Multiple trip reports describe excellent views of Mount Rainier, surrounding lakes, and nearby peaks. The peak features two summits (east and west) connected by an easy ridge traverse.

Sources: PeakBagger, WTA, AllTrails, Mountaineers

Route

Approach

Mirror Lake Trailhead (3,600 ft)

Directions: View on Google Maps

From I-90: Take Exit 62, turn right, drive 1.1 miles, and turn right onto Forest Road 5480. Drive 4.1 miles, going straight at the junction with Forest Road 5483 to stay on FR-5480, and reach a five-way junction at Lost Lake. DO NOT continue straight - instead, veer right to remain on FR-5480 and go around the east and north sides of the lake until reaching the Mirror Lake parking area(s).

Road Conditions: The forest road is in good shape as of late 2025. Trip reports indicate any car can make it to the trailhead, though the final 0.2 miles has deteriorated and high-clearance vehicles may have better access to the upper parking area.

Access & Permits

Permits & Regulations

• Northwest Forest Pass required for parking at the trailhead
• Alternative: National Parks/Federal Lands Annual Pass accepted

IMPORTANT: Do not cross the Cedar River Watershed boundary (marked with "No Trespassing" signs). Serious consequences apply for watershed violations.

Road Conditions

Roads within Mount Baker-Snoqualmie and Okanogan-Wenatchee National Forests are subject to seasonal closure. FR-5480 is typically accessible April through November.

Route Description

The route covers approximately 6 miles round-trip with 2,100 ft of elevation gain.

Typical completion times:

• 2.5-3 hours (~2 mph, 1000+ ft/hr): Trail runners, fit scramblers moving fast
• 3.5-4.5 hours (~1.5 mph, 700-800 ft/hr): Average fitness, steady pace with brief breaks
• 5-6 hours (~1 mph, 500-600 ft/hr): Relaxed pace, groups, taking time for photos

Approach (1.5 miles, ~300 ft gain): The trail begins gently, following the Pacific Crest Trail through old-growth forest. At approximately 1.3 miles, pass Cottonwood Lake on your right. Continue to Mirror Lake at 1.5 miles.

Boot Path to Summit (1.5 miles, ~1,800 ft gain): At Mirror Lake, cross the logjam at the lake's outlet and follow the way trail along the south shore for about 200 yards. Look for a faint path marked by ribbons heading south up the ridge. The unmaintained boot path ascends steeply through forest with roots, rocks, and occasional deadfall. Multiple trip reports note this steep forest section as the least enjoyable part but easy to follow.

After breaking out of the trees, the final few hundred feet offer open views and steeper, rockier terrain. The route remains Class 2 to the summit with one brief Class 3 section near the summit block. Trip reports emphasize staying on the correct boot path to avoid unnecessary Class 3/4 moves.

East to West Summit Traverse (0.25 miles, ~10 minutes): The traverse between Tinkham Peak (east summit, 5,398 ft) and the west summit (5,394 ft) is easy Class 1-2 along a broad ridge on the south side. Both summits have summit registers.

Crux

The crux is located near the summit block at approximately 5,200-5,400 ft, where the route steepens to Class 2+/3- terrain on rocky outcrops. Multiple boot paths exist near the summit block - trip reports consistently note that if you encounter Class 3 or 4 moves, you're off-route and should look for an easier line. The exposure is moderate on the SW face. In wet or icy conditions, rocks become slippery and extra caution is warranted.

Hazards

Route-finding: Multiple social trails around Mirror Lake can make finding the boot path tricky. Look for the path at the south shore, approximately 200 yards after crossing the logjam.

Steep terrain: The boot path is steep throughout, with sections of loose soil, roots, and rocks. Trekking poles highly recommended.

Cliff exposure: The north side of the summit has sheer cliffs with potential for fatal falls. Keep pets leashed near the summit. Exercise caution, especially in wet or icy conditions.

Weather exposure: The upper portion of the route is above treeline and exposed to changing weather. Summer thunderstorms can develop quickly.

Seasonal considerations:

• Summer (July-September): Best conditions. Bugs can be heavy at the summit and near water.
• Fall (October-November): Good conditions, fewer crowds, potential for early snow.
• Winter/Spring: Snow and ice on upper route. Microspikes or crampons may be required. Avalanche assessment needed.

Current Conditions

Daylight

For January 29, 2026, sunrise is at 7:33 AM and sunset at 5:04 PM, providing 9 hours 32 minutes of daylight. Civil twilight begins at 7:01 AM, useful for planning alpine starts.

Weather Forecast

The forecast shows an active winter pattern with light snow and cool temperatures through late January, improving to drier conditions by early February. Thursday brings light snow with 15.6mm precipitation and gusty winds. Friday continues unsettled with a rain/snow mix. Saturday offers a brief clearing with partly cloudy skies and no precipitation - the best weather window this week. Sunday through Monday return to wet conditions with rain/snow mix. The pattern improves significantly Tuesday-Wednesday with decreasing precipitation chances and warmer temperatures.

Summary: Saturday (Jan 31) offers the best weather window with clearing skies and no precipitation; avoid Thursday-Friday and Sunday-Monday due to active precipitation.

Freezing Level Alert (Peak: 5,398 ft):

• Thu-Fri (Jan 29-30): 1,300-2,500 ft (well below summit - expect snow at summit)
• Sat (Jan 31): 2,400-2,600 ft (below summit - snow/ice likely on route)
• Sun-Mon (Feb 1-2): 1,400-2,800 ft (below summit - snow/ice conditions)
• Tue-Wed (Feb 3-4): 3,200-3,400 ft (below summit - snow/ice possible on upper route)

Air Quality:

Air quality is good (AQI 32-42) during the forecast period. No air quality concerns for outdoor activities.

Check Current Forecasts:

• Mountain-Forecast.com - Summit-level forecast with multiple elevations
• Open-Meteo Weather - Detailed mountain weather data (source for this report)
• Open-Meteo Air Quality - Air quality forecast for this location
• NOAA Point Forecast - Official NWS forecast and alerts
• NWAC Mountain Weather - Cascades mountain weather (winter season)

Avalanche Forecast

Note: Current conditions (late January) warrant avalanche awareness on this route. The upper portion of Tinkham Peak has avalanche terrain.

Avalanche forecast not available. Check NWAC.us for current conditions before travel.

Trip Reports

Tinkham Peak has 648 total ascents logged on PeakBagger with 91 trip reports and 56 GPX tracks. WTA shows 80 trip reports. Most PeakBagger reports are brief (average <100 words), so WTA reports provide more detailed beta.

Most Detailed Reports

PeakBagger:

• 2024-09-15 - Patty Cokus - 461 words - Loop via Silver-Abiel-Tinkham, noted wet conditions, scrambly summit
• 2024-08-25 - Jared Jones - 413 words - Multi-peak loop with detailed route description
• 2024-08-09 - Jamie Yelland - 230 words - Silver/Abiel/Tinkham in that order
• 2024-08-31 - Paul Kallmann - 218 words - Mountaineers scramble, Windy Pass approach
• 2025-09-07 - Francisco Madera - 169 words, 📍 GPX - Recent detailed beta on difficulty

Washington Trails Association:

• 2025-11-16 - Mirror and Cottonwood Lakes, Tinkham Peak, Twilight Lake - Clockwise loop, late season conditions
• 2025-09-26 - Tinkham Peak - Detailed route description, road conditions
• 2025-09-20 - Silver Peak, Tinkham Peak - Multi-peak with photos

Browse All Trip Reports

• PeakBagger Ascents - Individual climb logs with optional GPX tracks and reports
• Washington Trails Association - User-submitted trip reports with photos and conditions (80 reports)
• AllTrails - User reviews and recent activity (514 reviews)

Information Gaps

• SummitPost access blocked: WebFetch returned 403 and cloudscrape.py returned limited HTML content. Check SummitPost manually for additional route beta.
• Avalanche forecast script not implemented: Check NWAC.us manually for current avalanche conditions (critical during winter months).
• No PeakBagger route data: The peak has no formal routes in PeakBagger database - route information synthesized from trip reports.
• Limited detailed PeakBagger reports: Most PeakBagger reports are <100 words. WTA provides more comprehensive trip reports.
• Mountaineers.org trip report extraction not attempted: Check Mountaineers manually for additional route information.

Data Sources

• PeakBagger: https://www.peakbagger.com/peak.aspx?pid=2222
• Washington Trails Association: https://www.wta.org/go-hiking/hikes/tinkham-peak
• AllTrails: https://www.alltrails.com/trail/us/washington/tinkham-peak-tinkham-east-boot-trail
• The Mountaineers: https://www.mountaineers.org/activities/routes-places/mirror-lake-tinkham-peak
• Open-Meteo Weather API: https://open-meteo.com/
• Sunrise-Sunset.org API: https://sunrise-sunset.org/

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Research completed 2026-01-29 using route-researcher v3.5.0 from the Claude Mountaineering Skills repository.