IntroductionThe Mary Green Glacier route is the most popular approach for Bonanza Peak. Starting at either Holden Pass or Holden Lake, this route involves steep & possibly waterfall-laden slopes, route finding, glacier travel, crevasse situations, scrambling, and rock climbing. A wide variety of mountaineering skills should be prerequisites for all climbers attempting Bonanza Peak. Attempting Bonanza Peak is a serious undertaking but one which is very rewarding once a successful summit is achieved.
I have divided the summit route into two major sections:
PART I: Climb To Bergschrund
PART II: Climb To Summit
PART I: Climb To BergschrundStarting at Holden Pass (~6400'), a use trail (if not snow covered) leads uphill towards the ridge located to the north and west directions. After several hundred vertical feet of gain, a large ledge (6700', possibly snow-covered) is reached. The route leads towards an infamous "waterfall slabs" slopes originating from the Mary Green Glacier. Scramble or steeply hike (depending on conditions) up near the waterfall slab slopes of the ridge. Try to find snowy ramps or slopes if possible and safer to do so.
Continue ascending until below a large rock cliff, and then side-traverse until reaching a basin located above most of the lower waterfall slabs. From the basin, begin to angle uphill for a while, heading towards the northeastern end of the Mary Green Glacier. Prior to reaching the gentler terrain of the Mary Green Glacier, a final very steep rock and snow slopes need to be ascended. It is good to rope-up for glacier travel once on the gentler terrain, if not already done so below the final steep slopes leading to the glacier.
When traveling across the Mary Green Glacier, it is typically best to traverse closer to its northern side. The southern side of the glacier has many crevasses and seracs, and tends to have snowmelt much sooner than the rest of the glacier. Dangers can still be encountered along the northern traverse, including crevasses (hidden or exposed), as well as avalanches and cornice-breaks from the steep slopes looming above on higher elevations of the peak.
After traversing across the northern side of the Mary Green Glacier, a steep snow thumb winds uphill, first west and then north. Use caution on this section, due to the steepness of the terrain in addition to the dangers previously mentioned. The steep snow thumb leads towards a massive steeply-angled bergschrund (~8600' elevation). For most parties, much of the key to a successful summit of Bonanza Peak requires this bergschrund to have some sort of snow bridge still present near its upper-right end. Without a snow bridge, the bergschrund crossing might be too difficult to attempt.
IMPORTANT: The bergschrund grows each day during Summer months. Pay attention to current conditions, including how large the snow bridge or crossing area is, as that location might increase in difficulty during daytime as snow/ice melt progresses.
Once across the bergshrund, the glacier climb is complete. Find a safe place to rest on sturdy rocky terrain before continuing.
PART II: Climb To SummitAbove/beyond the bergschrund, the final 900' of vertical gain involves a combination of scrambling and rock climbing. The standard route typically requires Class 3 scrambling, with some brief sections of Class 4 terrain, starting at a large steep gully above the bergschrund.
IMPORTANT: If the gully is completely full of snow, it still might be possible to steeply ascend using a combination of steep snow climbing and rock-scrambling along the sides of the gully where necessary. However, if the gully is a mixture of rock moats, snowy cracks, snowmelt streams, and icy underlayers, some potential summiters might instead opt to rock climb (roped) left of the gully on solid rock. Use good judgment for current conditions and rock climbing skills.
When in the large steep gully, the general rule is to climb up and stay right. After climbing several hundred feet of gain, traverse over into the next gully located to the left. Climb the second gully to an obvious notch in the northeast ridge. Turn south, following a brief knife-edge ridge (some Class 4) up to a final steep, exposed slope leading to the summit (9511').
When descending from the summit, many climbers rappel down several pitches until near the bergschrund. Some climbers might opt to downclimb the gully system (ascent route), while others might opt to do a combination of rappelling and downclimbing. From the bergschrund, descend the same route back to Holden Pass. If the waterfall slabs section is not snow-covered, a rappel might be required.
Essential GearRECOMMENDED GEAR: Glacier/climbing rope (50m-60m), helmet, sunglasses/glacier glasses, harness, rock climbing tools, 3-5 rock climbing slings, ice axe, poles, pickets, GPS, 10 Essentials
When To Climb This RouteThe steep slopes of Bonanza Peak, as well as the cornice-prone knife-edge summit ridge, make Winter and early Spring ascents typically unfavorable and dangerous. Most summit teams attempt Bonanza Peak between June-October, with most successful summit teams attempting the peak while the bergschrund can still be easily crossed but also while most/all snow is away from the standard rock scrambling route that begins above the bergschrund.
These favorable conditions typically occur between early-to-mid July during most normal snowpack years.