Welcome to the Thunderdome

A mother lode of ice and alpine routes in Montana’s Cabinet Mountains
Author: Scott Coldiron. Climb Year: 2018. Publication Year: 2019.

MARCH 2018

Our skis etch crisp lines in a crystalline mat of snow, broken only where we’d stopped to gawk at the deep icy couloirs and jagged buttresses of A Peak’s north face, towering 4,000 feet above. From our camp on the north shore of Granite Lake, the Thunderdome had looked like nothing but a bump under A Peak (8,634 feet), the second highest point in Montana’s Cabinet Mountains. But as we traverse the lake, the 1,800-foot Thunderdome slowly rises up until it blocks out A Peak entirely, and we can see the immensity of the icy veins coursing down its walls.

We gain the south shore and set a skin track up the snow gully before us. On our left, three tiers of quartzite cliff bands rim the lake. Cloaked in turquoise-tinged frozen cascades, it is a virtual playground of ice climbing. But our attention is drawn the other way as Matt Cornell, my climbing partner for this trip, gets his first up-close look at the Thunderdome. A broad river of blue ice spills off the tall buttress to the right. Hemmed in by slate-gray rock walls, the gully chokes down until just a white thread is visible, snaking to the summit. A few minute later we can see another stunning climb: burnished stone sheathed in ice so thin it shows the opaque tint of rock underneath, and dead vertical at its upper headwall. Two hundred yards upslope is a climb I’d done with Christian Thompson in 2014—Blackwell Falls (900’ WI5). It features a stunning 300-foot crux pillar, but we had been turned back by a dark, dripping chimney above, and the route had never been finished to the top of the wall. Today I think I see a glimmer of ice in the back of the chimney. Matt is no stranger to big ice climbs, but he looks awe-struck by the trio of huge ice formations above us. We decide on the middle line—the sheer headwall covered in thin ice will be our first big test in the morning.

In the far northwest corner of Montana, the Cabinet Mountains rise from the banks of the Kootenai River and cut 35 miles south to the Clark Fork. Approaches here are typified by long, steep-sided valleys teeming with old-growth forests of western red cedar and hemlock trees. In fact, the Cabinets hold one of the world’s few inland rainforests— some of these ancient cedars have been dated at over 1,000 years old. In addition to the animals one might expect to see in a Montana wilderness—grizzly, elk, moose, bighorn sheep, and plentiful deer—the Cabinets are also home to Canada lynx, wolves, and wolverines.

I first visited the Cabinet Mountains to climb in 2012 after hearing rumors of big ice formations at nearbyLeigh Lake. We found a half-dozen 500-foot ice climbs above the lake, and over the next two seasons I climbed there many times. But these routes lie at the bottom of Snowshoe Peak’s 3,800-foot north face. As I found out the hard way, this aspect holds an ungodly amount of snow, which it sheds with alarming vigor and regularity.

After two separate close calls with serious avalanches, I began searching out other likely terrain in the range, and I didn’t have to look far. Just over the ridgeline, a semicircle of cliffs above Granite Lake stood out immediately on Google Earth. I scoured the Internet, but I couldn’t find any record of winter climbing there, or even a single photo of the area in winter. Finally, in April 2014, my buddy Jonah Job and I made the 10-mile hike to Granite Lake to find the most impressive concentration of ice climbing either of us had ever seen.

In a stroke of geologic luck, the cliffs at the north end of Granite Lake form a natural amphitheater. Just above them lies the Blackwell Glacier, the last remaining glacier in the Cabinet Mountains. This bowl catches runoff from the massive flanks of both A Peak and neighboring Snowshoe Peak, creating an astounding amount of ice and giving the area an otherworldly feel. We began calling it the Thunderdome in reference to the apocalyptic battle arena from the 1985 movie Mad Max Beyond Thunderdome. In another happy coincidence for ice climbers, the Thunderdome stands proud of A Peak, diverting any avalanches that come off its north face.

The next couple of seasons saw little progress. as I spent the following winter in Patagonia and the year after broke my leg in an early-season ice climbing fall. By January 2018, I had fully recovered and I was champing at the bit to attempt the Thunderdome’s three biggest lines, but I was having a hard time finding partners. Perhaps with Bozeman and Canmore offering world-class ice climbing just off the road, skiing deep into the backcountry for first ascents held little appeal.We made a couple of trips in 2015, climbing a few smaller flows, but stormy weather and short days kept us off the big climbs. Finally, in March, I teamed up with Christian to climb the fantastic pillar of Blackwell Falls. The next month I returned with Jonah, Beau Carrillo, and Ben Erdmann. Our goal was the central couloir on A Peak’s north face, a deep gash that splits the tallest part of the face. The entry into the couloir, 500 feet of steep rock, had been scoured smooth by centuries of falling debris. This section appeared to be beyond our abilities and we decided to move on, but for me the hook was set—I vowed to be good enough to climb the couloir the next time I stood in this spot. We traversed along the base and found a moderate couloir with easier access. A day of ridiculously fun alpine climbing culminated in a steep rock and ice finish as we bagged the first ascent of Unprotected Fourplay (1,900’, AI4 M5).


I had grown frustrated and was working the nerve up to climb solo in the Cabinets when I got a call from an old friend.Brian White wasn’t calling about climbing but reaching out to a buddy in the midst of a devastating divorce. Despite the fact that Brian had only climbed ice a handful of times, I convinced him that a trip to the Cabinets would be the best medicine for his grief. By the end of the week, Brian had led his first pitch of ice: 150 feet of steep WI4—and a first ascent at that. We then made an attempt on the Thunderdome’s central couloir, but we just couldn’t move fast enough to finish the big route on a short January day.

Now I’d had a taste of the Thunderdome’s king line, and my desire to climb it was at a fever pitch. I went back in with Marlin Thorman a couple of weeks later, and we bagged a solid handful of multi-pitch first ascents. But without an adequate weather window, the big three still evaded me.

My luck changed when Conrad Anker visited Spokane and a chance meeting through a mutual friend led to us climbing together at our local dry-tooling crag. At last, someone’s excitement about the climbing potential in the Cabinet Mountains matched my own—Conrad and I began planning a trip. When events beyond his control forced him to cancel, Conrad thoughtfully found a replacement, introducing me to a young protégé from Bozeman, 23-year-old Matt Cornell. Matt hitchhiked to Spokane, and we immediately packed our gear along with six days of food, and drove to the trailhead outside of Libby, Montana.

After the long ski in, I messaged a friend on my inReach device to report on our progress.

-At camp with Matt, climbing tomorrow.

-Hey, I think Matt is the kid who lives in a closet under the stairs at my ex-boyfriend’s house in Bozeman.

“Hey Matt, do you live in a closet under the stairs?” I asked.

“Yup. It’s a pretty good-sized closet though.”

In fact, most of the year Matt is on the road—three months in Patagonia, a month and a half in Alaska, four months in Yosemite. His parents lent him the old family Subaru when he left home at 18 to pursue the climbing lifestyle. Three years ago, he deemed automotive costs to be holding him back, and he’s been without a car ever since. Each spring he rides his bike from Bozeman to Yosemite, and each fall he rides back. In short, Matt is one of the last dirtbag soul climbers.

Over the next five days, Matt and I climbed all three of the Thunderdome’s king lines: Mad Max (1,200’, WI5+), Road Warrior (1,100’, WI5 M5), and Master Blaster (1,500’, WI4 M5). At sunset on our last day, we topped out Master Blaster and stood on the summit of the Thunderdome. The gaping blackness of A Peak’s massive central couloir loomed overhead.

“I call it Devil’s Ass-Crack Couloir, what do you think?” I asked.

“Looks like a death-trap right now. I think it’s an early-season route—before the cornices are big and the avy danger is out of control.”

“Will you come back at the start of winter and give it a try with me?”

“Hell yes!” Matt replied.


In the predawn blackness, Matt and I are climbing, sliding, and crawling through a steep tangle of slide alder. I feel a stalk of Devil’s Club smack into my softshell pants—then the sting of thorns in my thigh.


Ducking under a snarl of slide alder, I clamber up out of the thicket. I feel a sudden tug from behind—a branch has caught on my pack—and I’m sprawling backwards and belly-up into the thorny patch of Devil’s Club.

“This is bullshit!”

“Hahaha…yeah,” Matt shouts back to me. “But it’ll be worth it if the couloir is in good shape.”

After three hours of arduous scrambling, we’re standing at the base of A Peak. The entry to the couloir is still more than 400 feet above us, the steep rock in between scoured featureless by centuries of falling debris. Hiking along the face, we finally spot the weakness we’d been hoping for—a hidden chimney that slashes across the face in the direction of the couloir. The slot provides a few pitches of gymnastic but fairly easy climbing, and then I find a vertical smear of blue ice leading directly to the couloir. A cloud of spindrift spills over the edge, and soon it’s a deluge, forcing me off the direct ice line.

Traversing right, I find a snowy ledge that diagonals into the couloir and suddenly we’re at the bottom of the abyss. Ramparts of gun-metal stone shoot overhead for hundreds of feet on either side. Matt and I climb at a furious tempo, thighs burning on steep snow slopes interspersed with rocky steps. The mixed climbing demands funky, physical movement, but we forge on through showers of spindrift up the unrelenting narrow slot.

The sun is low in the sky as I plow up another steep snow slope to a house-sized chockstone, then flop over the edge to discover a flat snow ledge, big enough to hold the tent we didn’t bring. Matt fires up the stove to melt snow as I stack the ropes and sort gear. Ramen noodles are the first real food we’ve had all day, and we watch the last amber rays of sunlight play across the walls overhead. A cornice overhangs the top of the wall, gleaming white in the sun. It doesn’t look far off.

After a brief rest we continue up, and after a couple pitches we’ve come up under a big roof—a conglomeration of huge boulders and choss. I belay under a constant shower of spindrift as Matt pushes on, determined to solve the puzzle overhead. Darkness falls and I see Matt’s outline dimly, my headlamp barely piercing the spindrift to illuminate Matt’s ghostly form. Light snow is falling, and soon pounding waves of spindrift funnel down the throat of the couloir.

Matt tries every option, methodically testing every possible move. He has been on lead for 90 minutes when I notice that I’m shaking uncontrollably.A storm is forecasted to hit in the morning, and our only way out is over the top—or all the way back down a 2,000-foot vertical bowling alley. If the storm hits while we’re in the couloir, we’re screwed. Wet, cold, and afraid, I am done, and at last I tell Matt I think we should bail. He agrees and we start our retreat.

After our first rappel, we pull the ropes but they won’t budge. We try every rope trick to no avail, so Matt clips in and jumars up the rope. A half-hour later, he reappears and the ropes pull free. The next rappel lands us back under the huge chocktone. I grab a rope and pull—it moves, barely. I pull again and the rope is stuck. It’s my turn to ascend, but Matt is already wrapping a prusik on and clipping in. It’s 3 a.m. when he returns and we’re finally able to pull the rope. The rope lands at our feet, and my heart sinks when I see it. A four-foot section looks someone has run it across a cheese grater, and the sheath is cut all the way through. Matt and I agree that we’re too close to making a fatal mistake, and we decide to wait for first light.

In a bid for style and speed, we’ve brought no bivy gear. Our down jackets are matted and lifeless. During the long night, we both solemnly swear that we’ll never return to this godforsaken place. The tight slot catches every bit of snow or rock that falls down the mountain, and it doesn’t seem worth the risk.

We begin rappelling again as dawn lights up the horizon, and six-and-a-half hours later we’re making the last rappel out of the couloir as the full storm hits. The first of many avalanches rips down the couloir as we pull the ropes for the last time. We stumble down to the lake and collapse in our sleeping bags.

The next day, a Thursday, I’m dead tired at the wheel, eyelids heavy, but I’m due back in town for a 48-hour shift at my job as a fire lieutenant in dowtown Spokane. I leave Matt on the side of I-90—he’ll hitch back to Bozeman just in time to make a Zion climbing trip.

It’s a busy shift—we’re up all Friday night on a three-alarm commercial structure fire. On Saturday, in between calls, I pull up the weather forecast: A beautiful window in the Cabinets is two days out. With Matt gone to the desert, I call my buddy Jess Roskelley just as he’s stepping off the plane from a climbing trip. Jess is stoked, so the plan is made. After a shift change on Sunday morning, I repack my bag, and by nightfall Jess and I are once again setting up camp at Granite Lake.

It’s mid-morning on Monday as I lead the steep blue ice that accesses the couloir—no spindrift to deal with this time. The sky is cobalt blue overhead and we make good time up the couloir, secure in the knowledge that we’ll have 2,000 feet of pre-rigged rap stations if we need to bail. This time we’ve packed a tent, and we pitch it under the big chockstone, sipping hot tea in our sleeping bags where Matt and I had shivered the night away just a few days before.

The next morning I’m warmed up by the time we reach the belay under the big roof, and Jess graciously gives me first shot at the crux lead—I’m determined not to let him down, and I feel a duty to Matt to finish the crux. I pull up onto the roof, clipping gear Matt had left. Then it’s on, and I power through the crux and pull the lip on solid hooks.

Just three pitches later, I’m belaying Jess as he navigates the final step. A steep wall with tricky climbing on loose blocks makes for a nice finish to a stellar climb. He flops over the edge and lets out a whoop. Jess and I stand on top of A Peak in the afternoon sun, laughing about my solemn promise from four days earlier.

Back at camp the next day, Jess pours us each a cup of Canadian whiskey, and we toast to Matt’s gutsy crux lead. His efforts at the end of a 22-hour push—climbing to the last hard move of the big roof, pulling on shifting cobbles in the pitch black, only to be shut down by pounding spindrift—had set us up for a relatively straightforward redpoint burn of Canmore Wedding Party (2,500’, AI5 M7).

At present, there are nearly 20 single-pitch ice climbs, eight multi-pitch ice and mixed routes, and two big alpine lines established on the Thunderdome and the A-Peak cirque. At least a dozen more routes are waiting to be climbed. A PDF mini-guide to the area is available: download it here

ABOUT THE AUTHOR: A native of western Montana, Scott Coldiron spent his teens planting trees in the foothills of the Cabinet Mountains. When he’s not exploring the mountains or writing about them, he works at a busy fire station in Spokane, Washington.

An interview with Scott Coldiron about the discovery of the Thunderdome ice arena is featured in episode 16 of the AAJ’s Cutting Edge podcast:

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