Route: Mailbox Peak - Dirtybox Peak - Granite Lakes Traverse (I-90 Corridor)

Mountain Information:

  Mailbox Peak

• Name: Mailbox Peak
• Region:  Central Cascades (I-90 Corridor)
• Summit Elevation: 4841 ft / 1476 m
• SummitPost Link: http://www.summitpost.org/mailbox-peak/150711
• Peakbagger Link: http://www.peakbagger.com/peak.aspx?pid=2102
• WTA Link:  http://www.wta.org/go-hiking/hikes/mailbox-peak-old-trail

Dirtybox Peak

• Name: Dirtybox Peak
• Region:  Central Cascades (I-90 Corridor)
• Summit Elevation: 4926 ft / 1501 m
• SummitPost Link: http://www.summitpost.org/mountain/510698
• Peakbagger Link: http://www.peakbagger.com/peak.aspx?pid=2106
• WTA Link: http://www.wta.org/go-hiking/hikes/dirtybox-peak

Driving Directions:

• Trailhead:  Mailbox Peak Trailhead
• Co-ordinates: 47.4666302,-121.6747634

• Address: North Bend, WA 98045

• Elevation: 800 ft
• Pass:  Discover Pass
• Directions: "Take exit 34 from I-90. Head north on 468th Ave SE for approximately half a mile until the intersection with the SE Middle Fork Road. Turn right onto the Middle Fork Road. Follow SE Middle Fork Road 2.2 miles to the stop sign at the junction with SE Dorothy Lake Road. Head left onto SE Middle Fork Road and drive .3 miles. Take the turnoff to the trailhead on the right and continue a short distance to the parking lot."
• Weather forecast
• Mountain Forecast
• National Weather Service
• Avalanche danger forecast
• Northwest Avalanche Center
  

Route Information:

• Gain: 4371ft
• Round Trip: 6-10 miles
• Difficulty: Winter Scramble
• Season: All year around
• Source: http://www.wta.org/go-hiking/hikes/mailbox-peak-old-trail
• Existing tracks: http://www.peakbagger.com/climber/GPXFile.aspx?aid=114993&sep=1
• Related Trip Report: http://www.peakbagger.com/climber/ascent.aspx?aid=114993
• Caltopo Route: http://caltopo.com/m/G6N1#
• Plan A:Traverse from Mailbox Peak to Dirtybox Peak and then follow the route back. RT 6.1 miles and gain 4300ft.
• Plan B: Traverse from Mailbox Peak to Dirtybox Peak and travel along the ridge toward Dirty Harry's Peak for 1800ft, then ascend to an abandoned logging road at point 4200ft. Take the logging road to Granite Lakes trail back to Mailbox Peak trailhead. RT 10.71 miles and gain 4371ft.

Misc 

• Videos: 
• Mailbox to Dirtybox Animation
• Mailbox Peak Loop 2014
• Other Links: 
• Mailbox-Dirtybox Traverse SummitPost
• DirtyHarry-Dirtybox-Mailbox traverse: nwhikers.net report 04/09/2015 and its Peakbagger report with GPS track. Pictures are available here.
• nwhikers.net report 1/13/2017
• yellowleaf report 12/09/2006
• Mailbox peak ascending from the north ridge
• Notes: 
• A more ambitious route is Mailbox-Dirtybox-Dirty Harry traverse as described in this report.
• As described in the summitpost page: "There are three variations of following the West Defiance Ridge from Mailbox Peak to Dirtybox Peak. One variation of the route follows the north/northeast side of the ridgeline. Another variation of the route basically follows the crest of the ridgeline between the two peaks. The third variation of the route follows the south/southwest side of the ridgeline."
• During winter, the north/northeast route is preferred: "During snowy traverses, following the gully on the north/northeast side of the ridge to the Dirtybox summit is most recommended and is YDS Class II. In contrast, following the crest of the ridgeline or the south/southwest side of the ridgeline alternate between YDS Class II and Class III (scrambling), have high exposures to avalanche dangers and rockslides, cornices to avoid (crest variation only), and might require technical climbing in places." The route is as follows: "If planning to follow the north/northeast side of the West Defiance Ridge to Dirtybox Peak, hike around the northwest (left) base of the first talus slope (~4600' elevation) of Mailbox Peak and circle around the north side of the mountain until below the east side of the summit."
• The above is proved by the most recent nwhiker.net report. The report stated: "We kept our microspikes on as we headed down the north ridge of Mailbox. About 150 ft below the top we changed into snowshoes which worked well. We continued down the north ridge for about another 50 ft where we started our traverse over to Garcia (Dirtybox). The map and an old report indicated a route between Mailbox and Garcia staying about 200 ft below the ridge between Mailbox and Garcia. As soon as we got off the north ridge we were breaking trail through the really nice snow we’ve been seeing this year. The views on the traverse looking north and east were really good! We traversed over to the northwest side of Garcia and went through trees up to the west ridge which we followed just a short distance to the summit. The ridge was really beautiful with some big old growth trees and small openings with southern views. The summit of Garcia had some trees blocking the north and northeast  views, but the south and west/southwest views were spectacular!". The path (#8) is drawn based on the above description. But some details are not very clear and we may need to update the route based on the snow condition.
• During summer, the ridgeline route is recommended. "During summer (non-snowy) traverses, following the crest of the ridgeline to the Dirtybox summit is most recommended because a faint dirt trail is exposed during much of the ridgeline despite still having both YDS Class II and Class III sections. In contrast, following the gully on the north/northeast side of the ridge would be a forested bushwhack, and following the south/southwest side of the ridgeline would be a steep bushwhack with exposure to rockslides." 
• Trekking poles are highly advised for all seasons. An ice axe is highly advised for snowy traverses.
• Topo maps: printouts