Isolation Traverse

The Isolation Traverse is one of the classic glaciated ski traverses in the Cascades, and is a big accomplishment for any skier. It features extensive glacial travel, the opportunity to ski off Eldorado Peak + the rugged peaks of the Snowfield group, the majesty of Backbone Ridge, and the inspiring Ice-Elation couloir.

If you've got the skillset and the drive, the Isolation Traverse is a worthy goal. But don't bite it off without proper experience: it is extremely serious and has no real bail options.

Multiday ski traversing is different than single-day tours (no matter how big they are). To even consider this tour, here's an incomplete collection of things you'll need.

• Extensive experience navigating large glaciers: you'll cross six large named glaciers. This shouldn't be your first time with glaciers unless you're being formally guided.

• Experience Winter Navigating in Bad Weather: The Isolation Traverse gets a ton of gnarly weather no matter what time of year, including gale-force winds, big winter storms, and regular white-outs.

• Experience Snow Camping: You'll almost certaintly be camping on snow for parts of this trip. This should not be your first snow camping trip.

• Experience Assessing Avalanche Conditions: This route travels through and beneath a ton of avalanche terrain. You need to be an expert at assessing snow stability in the field. There are no NWAC forecasts for this zone.

• Expert Backcountry Skiing Abilities: You’ll be skiing steep and complicated terrain on a huge variety of different snow types, from 45+ degree alpine slopes to frustratingly tight trees, all with an overnight pack on. A beginner will have a bad time.

• Experience rappelling with skis on your back: if you travel north, there's a mandatory rappel.

• Lots of gear: Some specifics are discussed below in the Equipment section.

• Solid fitness: you’ll likely be carrying your skis and overnight gear for multiple miles, on the way up and the way down.

• Enough general backcountry experience to make good decisions while deep in the wilderness. This can't be quantified, and only comes after spending lots of time in the mountains.

No one can decide when you’re ready to ski a traverse like this, and many backcountry skiers never do anything like this tour. But if you think you’re up to the challenge, the Isolation Traverse is an incredible tour.

Leave No Trace

If you choose to ski this route, please do your utmost to respect Leave No Trace principles, including carrying out everything that you bring in, from food and food wrappers to your feces (which should be blue-bagged and carried out). The North Cascades is an incredible place, and if we can all practice LNT principles, we'll be able to continue to visit this area for years to come.

The Basics

• Seasonality/Snow: This is a tough one. There’s generally enough snow to tour between December and June, but the tricky part is figuring out when you’ll find good weather and stable snow up there. The best time for this tour is probably April to mid-May, depending on how the snowpack is consolidating. Hit it too early and you'll deal with a ton of avalanche hazards. Too late, and the middle zone near Isolation Peak will be melted out, which is no fun.

• Snow Stability: This tour travels into a remote zone without NWAC forecasting. You’ll see a huge variety of snow conditions, and you’ll need to be making decisions constantly. Make sure to check the NWAC observations page before heading out, as your best bet for information is from someone who recently skied the zone. And post after your trip so others have a better idea of what they'll find!

• Road Access: The northern trailhead can be accessed year round. The southern trailhead (Eldo Trailhead) can get tricky depending on whatever horrible thing has happened to the Cascade River Road during the offseason (it regularly floods/gets blocked by huge trees or boulders). Make sure to scout the drive or get beta in the weeks before your trip to hear what things are like.

• Direction of travel: there are arguments for going either way, but most skiers will travel north, starting at Eldo. This means you get to descend the Backbone Ridge and ski the Ice-Elation Couloir. Both are standout portions the route, and you don't miss any cool descents by heading north.

• Number of Days:

  • It’s possible to do this tour in one single day, but you’ll need to be extremely fit, and you’ll miss out on the best parts of the tour - watching the sun set on the mountains adding on fun extra lines.

  • Most groups will do the traverse in three to four days, but make sure you’re taking enough time to allow you to add on any fun terrain you see! This tour will be described continuously, though it'll suggest places to camp so you can break it up as you see fit.

• Permitting

  • You'll need backcountry permits to camp in North Cascade National Park. Refer to this NPS website for the latest info, but be aware, camping in the Eldorado Peak and Snowfield Zones can be competitive, so take permitting seriously.

• Add-on options:

  • Ski Eldorado Peak - one of the Fifty Classic Ski Descents of North America.

  • Head off the route and ski Klawatti/Austera/Primus.

  • Romp around and ski/climb the rugged peaks of the Snowfield Group: Snowfield, Neve, Colonial, Paul Bunyan's Stump, and Pyramid.

  • Add-on anything else good you see - this terrain is chock-full of great runs in all directions.

Equipment

Depending on when you’re going and what the snow is like, you’ll need some equipment to keep having fun. There are the obvious things, including your backcountry ski/splitboarding setup, personal safety gear (helmets, goggles, medkit, etc.), and appropriate layers to keep yourself warm and dry. And then there's the technical gear and the overnight gear:

• Avalanche safety gear: beacon, shovel, probe, and the know-how to use it!

• Approach Shoes: You’ll almost certainly be doing some walking to get up to and down from the snow.

• Traction: Extra traction often helps on bigger ski traverses like this. This line requires thousands of feet of climbing and traversing on a huge variety of slopes. You will almost certainly need additional traction (beyond skins and boots).

  • Ski crampons: these will be essential, as large parts of this tour require high-consequence skinning across steep/glaciated slopes, no matter how icy it is.

  • Boot crampons: depending on conditions, you may need these, but they're always a good idea to bring along.

  • Lightweight ice axe and/or BD Whippet: it’s often icy early in the morning on the long traverses, and a fall in these areas would be extremely consequential. You will need, at a minimum, an ice axe in hand, but this can make icy skinning difficult. This terrain is perfect for a Whippet.

• Glacier Gear: You'll need a glacier kit. This means harnesses, rope, and materials to set up anchors and hauls, and the know-how to put it all together.

• Rappelling Gear: You'll almost certainly be rappelling to transition from the McAllister Glacier to the Backbone Ridge area. Bring the gear to do so.

• Radios: Radios are becoming more and more common in the backcountry skiing world, as they dramatically improve communication and safety, especially on more complex tours like this one.

• Overnight Gear: This shouldn’t be your first winter overnight trip - bring the right gear to keep yourself comfortable and safe.

• GPS/Navigation: You’ll need a GPS and a pre-loaded track for this tour, as navigation can get surprisingly tricky up in the high country.

A disclaimer on this description and included GPX track - this line was skied over three days with certain snow and avalanche conditions. The track described is a reasonable way to move through this terrain, and the description below mentions some of the hazards found during the trip. However, conditions may be significantly different when you visit this area. The advice in this trip report is not meant to be followed perfectly - you will need to adapt the route for the conditions you find and for your party’s abilities.

The Trip

Dropping Shuttle

Drop one car at the Pyramid Trailhead on Highway 20 and the other at the Eldo Trailhead on the Cascade River Road. Most folks will camp at the Eldo trailhead the night before their traverse.

Scouting the Cascade River Crossing

Take the time to scout the Cascade River crossing the night before. This is one of the sketchiest parts of the traverse, depending on the water levels. There are sometimes log bridges, but most of the time they're flushed downstream by the river, so you'll almost certainly be wading across. This area changes a lot from year to year, so be ready to range up and down the river to find a safe place to cross.

Up to the Alpine

Cross the Cascade River, get your shoes on, and prepare for a long climb. Within 3.5 mi, you'll be climbing 5,600' up extremely steep dirt. So get your slog on. At around 4,000', you'll leave the trees and break into the infamous boulderfields. If you're lucky, they'll still be covered in snow, but even if they're melted out, they're not that bad. Quest up them till you get to the continuous snow.

The Traverse Begins

Once you're on continuous snow, keep climbing to 6,250', where you'll transition to the Roush Drainage to the west, descending 100' down a steep couloir before beginning the final climb up to the Eldorado Glacier.

Cross the Eldorado Glacier and travel to the eastern base of the ridge off Eldorado Peak. There's great camping here, and if you like, you can drop some gear and ski Eldorado Peak - an incredible mountain with unbelievable views.

After finishing, head north across the Inspiration Glacier, cutting between the Tepeh Towers (some more semi-protected camping in this area) to access the McAllister Glacier, where you'll see a prominent col (on the map it's about 1,500' north of Pt 8,401'). This is probably the crux of the route. Figure your way up to the col, then rappel off the back - the height of the rappel changes depending on snowpack and season, but it's likely 25 to 50'.

Once you're on the west side of the col, head onto the unique Backbone Ridge - a 3+ mi long sloping descent (though you might need to do a climb or two) with unbelievable views the whole way. Cross the prominent ridge SW of "the Coccyx" before climbing through the upper Newhalem Creek drainage to a small pass at 6,600'. This marks the entrance to the Ice-Elation Couloir, a 1,500' descent down a gorgeous couloir.

After you've caught your breath, climb past the Newhalem Peaks to the Wilcox Lakes area. There's good camping in this area.

Next, leave Wilcox Lakes and head up the ridge toward Isolation Peak. If you like, you can summit, though you don't need to. Descend the ridge east off the summit. If you're a bold skier, there are some steep skiable couloirs to drop you straight north, otherwise skirt east until you can sneak north. No matter what you choose, this area has some steep no fall terrain.

From the unnamed lake northeast of Isolation Peak, begin a long climb up toward Snowfield Peak, traversing/climbing a very steep basin before reaching the Snowfield/Horseman col, where you can fit a somewhat protected snow camp.

Descend north across the Neve Glacier, enjoying the feeling of flying across a glacier on top of the world, before beginning your final climb up to the Neve Col, where there are several decent rock bivy's.

Ski down the Colonial Glacier and ski beneath exposed terrain under Pinnacle/Pyramid Peak before beginning the long descent to the car.

Leaving the Alpine

From the ridge east of Pyramid Peak, take a breather and enjoy the overwhelming views toward the Picket Range and Ross Lake before you descend into the forest. This final descent has been the site of a lot of schwacky epics, so make sure you're taking your time and have the GPS track up. You'll ski tight trees and steep slopes as far as you can down the ridgeline before transitioning to boots. Then scramble and schwack and downclimb your way down a painfully steep use trail. Things only improve when you get to Pyramid Lake at 2,600, where the trail becomes well-maintained. Crush the final few miles to your car and enjoy the dayhikers' stares.

Once back at the car, head a few miles east to Thunder Arm and congratulate yourself with a swim and a beverage, you just did a lot of work!

Participate in your backcountry community!

Congratulations, you just finished a pretty tough traverse! Please consider posting a trip report in the local backcountry skiing pages (Facebook, Turns-All-Year, etc.), as there are definitely other skiers who are eyeing this line and wondering about conditions! And also please consider submitting an observation to NWAC describing the travel conditions and snow stability you found! Submitting NWAC observations and writing trip reports on forums are great ways to contribute to the community and improve avalanche forecasts. It's also incredibly valuable to read the NWAC observations and trip reports written by others, as they'll help keep you updated on what the mountains are doing on a day-to-day basis. This will help determine whether you have a fun time next time you get out!