Looking across heather slopes at Unicorn Peak from The Castle in the Tatoosh Range in Mt Rainier National Park
Unicorn Peak viewed from The Castle during the Middle Tatoosh Traverse

Unicorn Peak + Thea Foss Peak + The Castle + Middle Tatoosh Traverse (Tatoosh Range, WA)

Trip Date: July 23-24, 2016

Unicorn Peak Climbing Trip & Middle Tatoosh Traverse:  Unicorn Col to Pinnacle–Plummer Saddle

Bench Lake
Snow Lake
Unicorn Col
Unicorn Peak (6917′)

Thea Foss Peak aka Manatee Peak (6524′)
Butter Lake
The Castle (6440′+)
Pinnacle–Plummer Saddle

Trip Report Summary

Region: Southern Washington Cascades

Sub-Region: Tatoosh Range

Area: Mt. Rainier National Park

Starting Point: Snow Lake Trailhead on Stevens Canyon Road (Elev. 4550 feet)

Way Points: Bench Lake & Snow Lake & Unicorn Creek Basin & Unicorn Col & Unicorn Glacier & Thea Foss Peak summit & Butter Lake & South Castle Ridge & Pinnacle-Plummer Saddle & Reflection Lakes Basin (trail hike & off-trail hike & rock scramble)

Ending Point: Pinnacle Peak Trailhead on Stevens Canyon Road (Elev. 4900 feet)

Campsite: Butter Lake bench (Elev. 6000 feet)

Summit: Unicorn Peak (rock climb via South Slope—South Face [Classic 5.6 Route] )

Summit: Thea Foss Peak (off trail hike via South Ridge; descent via West Slope)

Summit: The Castle (rock scramble & rock climb via East Face [Chimney Route] )

Approximate Stats: 6 miles traveled; 4400 feet gained; 4050 feet lost.

Full Trip Report

Eileen and I celebrated the unofficial first day of summer with a trip into the Tatoosh Range with Lisa L and Kevin L.  Together, we managed to tuck in Unicorn Peak—a summit that had been loitering around our wish lists for a long time.  Eileen and I extended our weekend with a traverse through the heart of the Tatoosh and a climb of The Castle.

Day 1: Trailhead to Butter Lake + Unicorn Peak Summit Climb

After dropping off our car at the Pinnacle Peak TH, we headed up the Snow Lake Trail in cool, foggy weather on Saturday morning.  Beyond the trail’s end, we ascended talus slopes to Unicorn Creek Basin.

climbers assending rocky blouder field in Unicorn Basin in the Tatoosh Range in Mt Rainier National Park
Climbing Up To Unicorn Basin

From the basin, nice snowfields and a snow couloir led up to 6600-foot Unicorn Col between the main and west peaks of Unicorn.  Crampons were handy here but not essential.

climbers booting up Unicorn snow couloir with cloud layer
Climbing Unicorn Couloir to Unicorn Col

We crossed through Unicorn Col and wrapped around the south side of the main peak on a climbers path, then hiked up a loose scree slope to the summit ridge.  The distinctive “horn” of the unicorn was visible to the north, and we could see three other climbers hanging on the face.

Unicorn's Horn as seen across a scree field on the shoulder of Unicorn Peak in the Tatoosh Range in Mt Rainier National Park
Unicorn’s Horn From Ridge

The horn is composed of surprisingly solid volcanic rock with plenty of cracks and blocky features.  There are three or four established routes on the south face, which is about 50 feet high.  Since we had two ropes and two racks, we split up to tackle this face.  Lisa and Kevin climbed the “Open Book Route” (5.0) while Eileen and I climbed the “Classic Route” (5.6).  Both were enjoyable climbs with good protection.  Lisa then went down and top-roped the latter route, as shown on the right side of the two photos below.

climbers on the broken rock, south face of Unicorn Peak Horn in the Tatoosh Range in Mt Rainier National Park
Eileen and Lisa On South Face
climbers on the south face of the horn of Unicorn Peak
Eileen and Lisa On South Face

After returning to Unicorn Col, we parted company.  Lisa and Kevin headed back to the trailhead to complete their day, whereas Eileen and I traversed over to a broad saddle northwest of Unicorn Peak.

Thea Foss Peak and Thea Foss ridge with a large snow field approach
Thea Foss Peak From Unicorn Col

We picked up a well-trodden path on the ridge crest and followed it up to Point 6524, which goes by names such as “Foss Peak” (in honor of Tacoma’s famous Thea Foss) and “Manatee Mountain” (for reasons unknown to me).  Personally, I prefer to call it “Thea Foss Peak” to distinguish it from Hal Foss Peak in the Olympics and from other Foss names in the Alpine Lakes Wilderness.

climber hiking green rolling ridge toward Thea Foss Peak with linguring snow patch in the Tatoosh Range in Mt Rainier National Park
Hiking Up Thea Foss Peak

Thea Foss Peak offers a wonderful view of Mt. Rainier.  Fortunately, the weather had cleared up enough for us to truly appreciate it.

climber sitting on the summit of Thea Foss Peak looking at Mt Rainier
Eileen On Thea Foss Peak Summit

From the summit, we dropped down to the west on easy grass slopes and found a nice camping bench near a little stream.  Still-frozen “Butter Lake” was just below our camp.

Descending Toward Butter Lake

Clouds filled all of the surrounding valleys as the sun set in a perfectly clear sky.  Throughout the night, we could see headlamps over on Mt. Rainier.

sunset on mountain ridge with valley fog in Mt Rainier National Park
Sunset From Camp

Day 2: Butter Lake to Trailhead + The Castle Summit Climb

In the morning, we descended to Butter Lake, then ascended a few hundred feet to the base of The Castle.  We forgot to bring any beta for this peak, but there appeared to be a weakness in the facade just left of center.

rocky pinnacles of the east face of The Castle on the Tatoosh Range in Mt Rainier National Park
The Castle East Face

The weakness turned out to be an obvious crack-chimney system that ended at a tiny notch adjacent to a rappel horn.  Two short pitches up this crack-chimney (5.0) and a brief scramble along the exposed crest put us on top.  Again, the volcanic rock was uncharacteristically solid.

mountain climber on the summit rock horn of The Castle in the Tatoosh Range in Mt Rainier National Park
Scrambling Along The Castle Summit Ridge

Unicorn Peak stood out like a stone beacon on the eastern horizon, and this view only added to a little mystery that began yesterday.  While we had sat on Unicorn’s “summit horn,” we noticed that the rocky dome several hundred yards to the south seemed a bit higher.  From a distance, the horn appeared a bit higher, but the USGS map clearly places the vertical-control “X” on the “dome” rather than the “horn.”  I wish that I’d taken my sighting level up the peak yesterday.

Unicorn Peak in the distance with the Thea Foss ridge with snow patches in the Tatoosh Range in Mt Rainier National Park
Unicorn Peak From The Castle

We could have stayed longer on The Castle, but a group of six Mazama Club climbers started to arrive.  We rappelled down their fixed rope, scurried down to the obvious bootpath below the crag, and followed it over to the Pinnacle-Plummer Saddle.  This being a beautiful summer day, the saddle was swarming with day hikers.  A golf-cart-worthy trail took us the final 1.5 miles down to our car at the Pinnacle Peak TH.

Route Map & Profile

Middle Tatoosh Traverse Route Map (CalTopo)

Middle Tatoosh Traverse Route Profile

Click to enlarge…