Mailbox-Dirtybox Traverse

Page Type Page Type: Route
Location Lat/Lon: 47.45803°N / 121.63321°W
Additional Information Route Type: Hiking, Mountaineering, Scrambling
Seasons Season: Spring, Summer, Fall, Winter
Additional Information Time Required: Most of a day
Sign the Climber's Log

Overview

The Mailbox-Dirtybox Traverse is the most popular approach for Dirtybox Peak in Washington State. This route is also the shortest approach to the summit of Dirtybox Peak. The route has two major sections:
The first section of the route begins by following the Mailbox Peak Trail to the summit area of Mailbox Peak.
The second section of the route follows the West Defiance Ridge southeast to Dirtybox Peak. The Mailbox Peak Trail section of the route is YDS Class I, while the West Defiance Ridge section of the route ranges between YDS Class II and Class III (depending on variation).

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.
Cornice Along Mailbox-Dirtybox TraverseCornice Atop West Defiance Ridge

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.

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.

Route Description

Mailbox-Dirtybox TraverseHiking East Along Steep Ridgeline

1) From the Mailbox Peak Trail parking area, hike approximately 0.25 miles to the Mailbox Peak Trailhead.

2) Follow the Mailbox Peak Trail for 2.5 miles to the summit (4841' elevation) of Mailbox Peak, gaining 4000' elevation during the trail. The summit is the preferred destination is planning to follow the crest of the West Defiance Ridge to Dirtybox Peak. The rest of the directions continue with Step #3. If not planning to follow the crest of the ridgeline, see variations listed below (Steps #2a and #2b).
2a) RIDGE VARIATION: 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.
2b) RIDGE VARIATION: If planning to follow the south/southwest side of the West Defiance Ridge to Dirtybox Peak, hike around the south (right) base of the first talus slope (~4600' elevation) of Mailbox Peak and circle around the south side of the mountain until below the southwest side of the West Defiance Ridge.

3) Follow the ridge for 0.5 miles to the summit (4926' elevation) of Dirtybox Peak.

Getting There

Driving Directions For Most Popular Approach (From Mailbox Peak):



1) Follow I-90 until several miles east of North Bend, Washington.
2) Take Exit 34 (468th Ave. SE). Head north.
3) After 0.6 miles, turn right onto SE Middle Fork Road.
4) After 0.9 miles further, the road splits. It does not matter which side to choose, as both roads rejoin 1.0 mile further.
5) The Mailbox Peak Trail parking area is approximately 0.25 miles after where the roads rejoin each other. A blue gate is on the rightside of the road, marking the entrance to the route.

Essential Gear

Trekking poles are highly advised for all seasons. An ice axe is highly advised for snowy traverses.

Parents 

Parents

Parents refers to a larger category under which an object falls. For example, theAconcagua mountain page has the 'Aconcagua Group' and the 'Seven Summits' asparents and is a parent itself to many routes, photos, and Trip Reports.