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Created November 6, 2025 23:17
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Granite Mountain (5,632 ft) - Route Beta Research - I-90 Corridor, WA
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2025-11-06-granite-mountain.md

Granite Mountain - Route Beta Research (2025-11-06)

⚠️ 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

Granite Mountain rises to 5,632 ft (1,717 m) with 1,161 ft (354 m) of prominence in the Cascade Range, King County, Washington. The peak is located at 47.417645°N, -121.481395°W (Google Maps | USGS Topo). The standard route is a strenuous day hike rated hard/class 2 with some light scrambling near the summit.

This is one of the most popular hikes on the I-90 corridor, featuring a historic fire lookout at the summit with spectacular 360-degree views of Mount Rainier, Mount Stuart, the Alpine Lakes Wilderness, and surrounding peaks. The route climbs steeply through forest before breaking into subalpine meadows and talus fields, with the final approach navigating rocky terrain to the lookout.

Sources: PeakBagger, AllTrails, WTA, SummitPost, Mountaineers

Route

Approach

Pratt Lake Trailhead (Exit 47 off I-90)

From Seattle, take I-90 eastbound to Exit 47 (signed for Snoqualmie Pass/Tinkham Road). Turn left at the stop sign to cross over the freeway, then turn left at the T-intersection onto Forest Road 9035. Continue 0.4 miles to the Pratt Lake Trailhead parking area.

Directions: View on Google Maps

Access & Permits

Permits & Regulations

  • Northwest Forest Pass or America the Beautiful Pass required for parking ($30/year for NW Forest Pass, $80/year for America the Beautiful Pass)
  • Alpine Lakes Wilderness Permit required May 15 - October 31 (free, self-issue at trailhead)
  • Maximum party size: 12 people
  • Toilet available at trailhead
  • Parking capacity: ~35 vehicles (frequently fills by mid-morning on weekends; additional roadside parking available)

Road Conditions

Summer Access (May-Oct): Forest Road 9035 is typically open and passable for passenger vehicles.

Winter Access (Nov-Apr): FR 9035 may not be plowed. Park on the frontage road near the freeway if the road is snow-covered, adding approximately 0.4 miles to the approach.

Route Description

The route covers approximately 8.0-8.6 miles roundtrip with 3,800 feet of elevation gain.

Typical completion times:

  • 2.5-3.5 hours up (~2+ mph, 1000+ ft/hr): Experienced hikers, trail runners
  • 3-4.5 hours up (~1.5-2 mph, 700-900 ft/hr): Average fitness, steady pace with brief breaks
  • 4-5.5 hours up (~1-1.5 mph, 500-700 ft/hr): Relaxed pace, groups, taking time for photos
  • Total roundtrip: 5-10 hours depending on pace and time spent at summit

Detailed Route:

Begin on the well-maintained Pratt Lake Trail (#1007), following it for 1.2-1.3 miles through cool, mossy forest. The trail gains elevation gradually on this section. Watch for the signed junction where the Granite Mountain Trail (#1016) branches right—this is your route.

After the junction, the trail immediately steepens with continuous switchbacks through forest. The grade is sustained and gains elevation quickly. After approximately 1 mile from the junction, the trail crosses a seasonal avalanche chute—this is the area of significant avalanche danger in winter and spring that has resulted in fatalities. In summer, this is typically a straightforward crossing.

Beyond the avalanche chute, the trail traverses eastward, breaking out of dense forest into increasingly open terrain. The route enters subalpine meadows with spectacular wildflowers in season (typically late July-August). Views begin to open up with glimpses of surrounding peaks.

The final section navigates increasingly rocky, talus-laden terrain. The trail becomes rockier and can slow your pace as you navigate around and over boulders. There may be some light scrambling on rock steps, though the difficulty does not exceed Class 2-3. In early season (typically through mid-July), snow may cover portions of the upper trail, requiring microspikes.

The summit features a historic fire lookout (Granite Mountain Lookout) perched dramatically on the rocky summit. The lookout offers stunning 360-degree views including Mount Rainier to the south, Mount Stuart to the north, and numerous Alpine Lakes peaks.

Route Variations:

  • Summer Route: Follows switchbacks around the talus slope west of the summit
  • Winter Route: Ascends directly over the snow-covered talus when conditions are stable; requires avalanche awareness training

Crux

The crux is the upper talus field beginning around 5,000 ft, where the trail becomes increasingly rocky and boulder-strewn. While technically straightforward (Class 2), the sustained steep grade combined with loose, ankle-rolling rocks can be physically demanding and requires attention to foot placement. In wet or icy conditions, rocks become slippery and the difficulty increases. Early season ascents may encounter snow-covered talus requiring microspikes for safer travel.

Hazards

CRITICAL - Avalanche Danger:

⚠️ This route crosses a major avalanche path and has a history of fatal avalanche accidents in winter and spring. The Mountaineers notes: "Avalanches have killed and injured climbers on this mountain in April and May."

  • The route is extremely dangerous from approximately November through May, and potentially into June depending on snowpack
  • DO NOT attempt this route in winter or spring without:
    • Current avalanche forecast review (NWAC.us)
    • Avalanche awareness training (AIARE Level 1 minimum)
    • Proper avalanche safety equipment (beacon, shovel, probe)
    • Experience evaluating avalanche terrain
    • Stable weather and snowpack conditions
  • The avalanche chute is crossed approximately 1 mile above the trail junction

Other Hazards:

  • Rocky terrain: Loose, ankle-rolling rocks on upper trail and talus fields; careful foot placement required
  • Weather exposure: Upper meadows and summit are fully exposed to weather; conditions can deteriorate rapidly
  • Route-finding: Trail can be obscured by snow in early season; route-finding skills necessary
  • Steep grades: Sustained steepness can cause exhaustion; pace yourself and take breaks
  • Crowding: This is an extremely popular trail; expect crowds on summer weekends

Seasonal Considerations:

  • Winter/Spring (Nov-May): Avalanche danger, snow-covered trail, potential whiteout conditions
  • Early Summer (Jun-Jul): Lingering snow patches, potentially wet/muddy trail, wildflowers begin
  • Mid-Summer (Aug-Sep): Best conditions, dry trail, peak wildflower season (early August)
  • Fall (Oct-Nov): Fall colors (late September-early October), increasing precipitation, early snow possible

Current Conditions

Daylight

For November 6, 2025, sunrise is at 6:56 AM PST and sunset at 4:42 PM PST, providing 9 hours 46 minutes of daylight. Civil twilight begins at 6:25 AM PST, useful for planning alpine starts.

Weather Forecast

The forecast shows a significant winter storm system arriving today (Wednesday) bringing rain and snow to the area. Today features rain transitioning to snow after 10 PM with lows around 30°F and 1-3 inches of snow accumulation possible. Winds from the WSW at 13-16 mph with gusts to 26 mph.

Friday continues snowy conditions before 2 PM with highs near 34°F and wind chills between 20-29°F. The weekend offers improving conditions with partly sunny skies Saturday (high 37°F) and Sunday (high 43°F), though another wet system approaches early next week with rain likely Monday-Wednesday.

Summary: Current conditions are transitional to winter with snow arriving tonight. Avalanche hazard will be elevated. Weekend offers a brief weather window before the next storm cycle.

🏔️ Freezing Level Alert (Peak: 5,632 ft):

  • Thu Nov 6 (Today): 5,348 ft (BELOW summit - expect snow/mixed conditions)
  • Fri Nov 7: 3,510 ft (well BELOW summit - expect all snow)
  • Sat Nov 8: 3,900 ft (well BELOW summit - expect snow)
  • Sun Nov 9: 4,070 ft (well BELOW summit - expect snow/mixed)
  • Mon Nov 10: 3,190 ft (well BELOW summit - expect snow)
  • Tue Nov 11: 2,930 ft (well BELOW summit - expect snow/mixed)
  • Wed Nov 12: 2,890 ft (well BELOW summit - expect snow)
Day Conditions Temperature Precipitation
Thu Nov 6, 2025 (Today) 🌧️❄️ Rain/snow mix, becoming all snow High: 34°F / Low: 27°F 34.9mm (100% chance)
Fri Nov 7, 2025 ❄️ Snow High: 23°F / Low: 21°F 18.6mm (68% chance)
Sat Nov 8, 2025 🌤️ Clear to partly cloudy High: 34°F / Low: 21°F None (8% chance)
Sun Nov 9, 2025 ⛅ Partly cloudy High: 37°F / Low: 25°F None (21% chance)
Mon Nov 10, 2025 ⛅ Partly cloudy High: 36°F / Low: 30°F 10.1mm (59% chance)
Tue Nov 11, 2025 ⛅ Partly cloudy High: 37°F / Low: 28°F 0.3mm (49% chance)
Wed Nov 12, 2025 ⛅ Partly cloudy High: 41°F / Low: 27°F None (61% chance)

Air Quality:

Air quality is good (AQI <50) during the forecast period.

Check Current Forecasts:

Avalanche Forecast

⚠️ Given current snowfall and transitional conditions, check NWAC.us for current avalanche forecast before attempting this route. The route crosses a major avalanche path with a history of fatal accidents.

Trip Reports

Granite Mountain is extremely well-documented with 2,094 total ascents recorded on PeakBagger, including 123 in the last year (14 with trip reports). The peak also has 1,942 trip reports on WTA, making it one of the most heavily reported hikes in Washington. Most PeakBagger trip reports are brief logs (averaging ~20-50 words), while WTA reports typically provide more detailed conditions and route information.

Most Detailed Reports

Washington Trails Association:

PeakBagger:

  • 2025-10-21 - Susan Shih - 📝 Brief report, 📍 GPX - "Lollipop loop up the ridge and down the trail on a beautiful fall day. Snow on the ridge's boulders made for slower going."
  • 2025-09-16 - Wyatt Freeman - 📝 Brief report, 📍 GPX - "Scrambled the furthest east gully on the way up to shortcut the trail. Couple harder moves, but all 3rd class feeling."
  • 2025-09-06 - Selena Eon - 📝 Brief report - Off-trail route to Crystal Lake and Tuscohatchie Lakes

Browse All Trip Reports

Information Gaps

  • Sunrise/sunset times: API returned UTC times that need manual conversion. Verify local sunrise/sunset at TimeAndDate.com
  • SummitPost access: WebFetch failed (403 error); successfully retrieved via cloudscrape.py fallback
  • PeakBagger trip reports: Most reports are brief logs (20-50 words). WTA is recommended for detailed trip reports
  • Avalanche forecast: Script not implemented; manual check at NWAC.us required
  • Winter conditions: Limited winter trip reports in recent data; winter ascents are rare due to extreme avalanche danger

Data Sources

Research completed 2025-11-06 using route-researcher from the Claude Mountaineering Skills repository.

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