The Bomber Traverse Map

The Bomber Traverse is an informal hut-to-hut wilderness backpacking route in the Talkeetna Mountains of Alaska. The purpose of the Bomber Traverse Map is to aid wilderness travel by indicating general backcountry routes and hut locations, by codifying locally-accepted names for peaks and other features, and by documenting rapid changes in glaciation.

Background

In August 2012, I set out with a group of three other hikers from the MCA Rainery (Mint) Hut to climb Backdoor Gap, cross Pennyroyal and Bomber Glaciers, and return to our cars via the Reed Lakes trail. We planned to cross a pass between the glaciers known as “Bomber in a Day Gap” because it allows a truncated version of the Bomber Traverse that shaves some time and distance from the full traverse. When we set out we expected a challenge: the Talkeetnas are riddled with loose rock, steep slopes and glacial ice. But we weren’t expecting our maps to lead us–literally–off a cliff.

We crossed Pennyroyal in a flurry of August snow, and scrambled to the top of the rocky pass leading to Bomber Glacier. On our USGS maps, this pass appeared to be a shallow ribbon of rock between the two sweeping masses of ice. But as we climbed down toward Bomber Glacier, the terrain rolled over more and more abruptly and we found ourselves threading steep, wet ledges of glacier-carved granite strewn with loose rock and slippery snow.

Ryan Kenny descending “Bomber in a Day Gap.”

Just a few dozen feet above Bomber Glacier, one of our group slipped, tumbled down the rocky face, bounced over a deep randkluft (a crevasse-like feature formed when the top of a glacier melts away from the headwall behind it) and landed on the glacier. She was unhurt but shaken, and after we made sure everyone was safe we asked the unavoidable question:

Where the %&$#?@ did this cliff come from?

A look at the USGS maps and the surrounding terrain features quickly provided the answer: the glaciers had receded. A lot. The glacier we were standing on had lost about a third of its length since our maps were made, and at least a hundred feet of depth. The cliffs we had struggled down had always been there, but until recently they’d been hidden under glacial ice.

Glacial recession in the Talkeetna Mountains is more than a collection of abstract data points. Our experience in 2012 demonstrated that for Alaska outdoorspeople, deglaciation is a practical issue with major implications for safe travel.

The Bomber Traverse Map – The Basics

The current edition of the Bomber Traverse Map is made up of four merged quads of the 2016 USGS 7.5-minute maps, with hut locations, routes, place names, relief shading and glacial recession data overlaid onto them.

I used the 2016 USGS maps because their elevation data is generally more accurate than previous maps, and includes topographic changes caused by glacial recession. However, the 2016 maps provide their own challenges and frustrations: many lakes that had been included in older USGS maps are missing, as are many man-made landmarks such as old mine sites. And while the 2016 maps do contain more accurate representations of glaciers in their current states, they are already significantly outdated and some glaciers–such as the large, crevasse-riddled Wintergreen Glacier–are missing entirely.

The Bomber Traverse Map therefore attempts to improve upon the 2016 maps both by adding additional information and by correcting clear mistakes.

Mapping Glacial Recession in the Talkeetna Mountains

The topographic data (including glacier boundaries) compiled in the 1950s was used on USGS maps without apparent updates until at least 1994. Many online and device-based mapping apps continue to use this data as a base layer. The Bomber Traverse Map overlays the glacial boundaries recorded around 1950 onto the 2016 maps (and adds glaciers missing from the 2016 maps).

Example of glacial recession mapping. On the left is a 1950s USGS map, showing a 1.4-mile-long glacier between Triplemint Spire and Telemint. In the middle is the 2016 USGS map, indicating a much smaller glacier. On the right is Edition 2.1 of the Bomber Traverse Map. The Bomber Traverse Map overlays the glacier outline from the 1950s maps onto the 2016 map, emphasizes the boundary of the glacier on the 2016 map, and adds additional data.

Glaciers that appear on the 1950s maps but do not appear on the 2016 maps are marked with a red “X” to indicate that they have apparently disappeared.

Implications of Glacial Recession

Why not simply show the most accurate current glacial boundaries? Why indicate the historical extent of glaciers at all?

Understanding glacial change is helpful for backpackers much the way that knowing historical low-tide and high-tide water levels might be helpful for a boat captain. It allows backpackers to better avoid hazards, anticipate terrain, and navigate through a changing environment.

As we experienced on our hike over Bomber in a Day Gap in 2012, a glacier in recession is more likely to uncover challenging terrain that is not yet reflected on any maps. A cliff of only ten to twenty feet can create a significant hazard. Many glaciers in the Talkeetnas have lost at least ten times this much ice since the 1950s maps were published.

Recently glaciated terrain is often difficult to move through because it has not had time to settle and stabilize. This is true of moraines left at the retreating front edge of a glacier, but it is especially true of loose rock at a glacier’s headwall. In many glacial cirques in the Talkeetna Mountains, rock has fallen from mountainsides, piled up and fanned out onto the top of glaciers. Because the foundations for these rock piles are actively shrinking, they never have an opportunity to fully settle. One prominent example is the notoriously unstable rock fan on the northeast side of Bomber Pass, which rests on the top of Bomber Glacier.

Brett Frazer and Tim Treuer stand in the midst of a recently-glaciated valley below Montana Peak

Receding glaciers have left behind many small lakes, moraines, and other features that may have implications for backcountry navigation. For example, no maps currently in use show the small lake forming off the nose of Snowbird Glacier, to the northwest of the Snowbird Hut. Knowing the rate of glacial recession gives a backpacker a better frame of reference when encountering unexpected terrain.

Last, and perhaps more importantly, considering deglaciation is an interesting and perhaps even obligatory exercise for people in the twenty-first century. I hope that the Bomber Traverse Map helps those both in and outside of the outdoor community conceptualize the effects of climate change and consider the power of our actions in the Anthropocene.

Local Names

Only a few of the tallest peaks and drainages in the Talkeetna mountains carry “official” names recognized on USGS maps. But the mountains, lakes, and other land forms are too close to Alaska’s population centers and too heavily visited to remain nameless. Over the last several decades, local names for many land features have gained broad (if not totally unanimous) acceptance. Codifying place names aids logistics and improves safety for backcountry users.

To determine place names for the Bomber Traverse Map I referred to handwritten maps left at the Snowbird, Bomber and Rainey (Mint) Huts and to online and personal maps maintained by well-known Alaska outdoorspeople. When there was a conflict between maps, I reached out to map authors and consulted satellite imagery, USGS maps, and members of the outdoor community.

Some maps contained conflicting information that could not be reconciled. For example, the handwritten map at the Snowbird Hut put “Nevada Peak” north of Gnome Lake, where other maps put that name on another peak many miles away, just south of Telemint Glacier. The most common conflicts with names simply involve spelling. Take, for example, the prominent peak directly north of the Bomber Hut. Maps variously spelled the name of this peak “Neltura,” “Nalteni,” and “Nelteni.” According to several sources, this peak was named after the indigenous Dena’ina word for “Thunder”. I consulted a Dena’ina dictionary and found that “Nelteni” seems to be the correct spelling.

From left to right: 1) Handwritten map in the Rainery (Mint) Hut, 2) Handwritten map in the Snowbird Hut, 3) William Finley’s online map, 4) Steve Gruhn’s map, 5) The Bomber Traverse Map, ed. 2.1. Note the different spellings of both Nelteni and Teni Weni.

Determining place names requires judgment and discretion. Ultimately, the names we give places are arbitrary and imposed. Most peaks, valleys, and streams in the Talkeetna Mountains remain nameless, and in this vast and little-tracked wilderness area that seems appropriate. If you believe I have made an error or would like to make a suggestion for future editions of the Bomber Traverse Map, feel free to get in touch.

The Bomber Traverse Route

The Bomber Traverse is an informal, unofficial route through the Talkeetna Mountains wilderness. It is not a trail. The Traverse winds around cliff bands and over boulder fields, and crosses multiple glaciers with constantly-changing surface hazards. There is no single best way to complete the Traverse, and the optimal route changes with the conditions. Glacial recession will cause routes to change significantly over the coming decades.

The routes indicated on the Bomber Traverse Map are based on online research, personal experience, and GPS tracks from myself and others. I’ve tried to place the route on what I believe is the safest, easiest way through this wilderness area. However, users should always react to the conditions and rely on judgment in order to stay safe.

Note that the Bomber Traverse Map shows summer routes. Winter routes will be different, especially because they must consider avalanche risks.

Route changes from the Bomber Traverse Map between editions 1.1 (left) and 2.1 (right). Starting with edition 1.2 I moved the route to avoid the steep, slippery cascade below Snowbird Glacier, and lead backpackers down the Bartholf Creek drainage on shallower terrain. These changes were made after a boots-on-the-ground trip in August 2017.

Bomber Traverse Huts

The Bomber Traverse Map includes markers and GPS coordinates for the Snowbird, Rainery (Mint), Bomber, Dnigi, and Seth Holden huts. Current information about the huts can be found on the American Alpine Club and Mountaineering Club of Alaska websites.

The Bomber Traverse huts are maintained entirely through volunteer efforts and donations. By law, all huts are open to the public. However, if you plan on using them, please donate or sign up for membership with the Mountaineering Club of Alaska and the American Alpine Club. Please treat the huts respectfully and clean them thoroughly when you leave so that they’re ready for the next group!

The Mint Hut, with Doublemint, Peppermint, and Triplemint Spires in the background

Map Editions

• Edition 2.4 – 19MB JPG – Published August 2022 – Edited routes between Eska Falls and Dnigi Hut, Dnigi Hut and Seth Holden Hut, Seth Holden Hut and Bomber Hut, Bomber Pass and Bomber Hut. “Added high route” between Bomber Hut and Seth Holden Hut. Added names (Sobriety Glacier, Atonement Glacier, Blazing Saddle, Troublemint Glacier, Ozone Glacier). Added notes about two newly-formed lakes. Updated compass declination.
• Edition 2.3 – 19MB JPG – Published August 2021 – Edited routes between Snowbird and Bomber Huts, and between Bomber Hut and bomber wreckage. Updated compass declination.
• Edition 2.2 – 50MB PNG – Published September 2019 – Corrected minor distortion of map and scale.
• Edition 2.1 – 50MB PNG – Published August 2019 – Re-centered map to include Dnigi and Holden Hut areas. Moved peak and feature locations (Sobriety Pass, Mt. Yisbo). Edited glacier boundaries (Wintergreen Glacier). Added huts (Holden Hut, Dnigi Hut) and routes between huts. Added names (Mt. Observatory, Elbow Pass, Dnigi Peak, Vegetarian Peak, South Fork Kashwitna River, Wintergreen Creek, Tsili, Kommando Col, Nelteni Saddle, Ozone Pass, Morning Glory Peak). Changed name (Penny Royal Glacier to Pennyroyal Glacier). Major changes to map design, many edits to legend. Thanks to Dave Staeheli, Fred Trimble, Michael Myers, and Steve Gruhn for their suggestions, comments, and patience.
• Edition 1.3 – 51MB PNG – Published November 2017 – Added names (Snowbird Village Site, Lane Hut Site, the Monolith, Kendalmint, Tenemint). Added relief shading. Corrected mistake on legend re: glacier boundaries. Thanks to Fred Trimble for creating the relief shading layer, suggesting new ways to distribute digitally, and providing additional place names.
• Edition 1.2 – 36MB PNG – Published September 2017 – Changed names (Didilkama to Didilkama Peak, Yisba to Yisbo Peak, Lower Spire to Lower Tower, Teeny Weeny to Teni Weni, 3-Bell Spire to Three Bell Spire). Added names (Friendship Pass, Rae-Wallace, Black Prospect, Marmot, Peak 4068). Edited glacier boundaries (Wintergreen Glacier, unnamed glacier remnant above Upper Reed Lake). Moved peak locations (Yisbo Peak). Improved Bomber Traverse routes (Snowbird Hut to Bomber Hut, Bomber Hut to Bomber Pass). Removed notes about deficiencies in USGS maps–glaciers mistakenly omitted from 2016 maps are added in without notation. Slight changes to terrain notes and map legend. Thanks to Bretwood “Hig” Higman, Lang VanDommelen, Steve Gruhn, and William Finley for their suggestions and assistance.
• Edition 1.1 – 36MB PNG – Published August 2017

Anchorage biologist Tim Treuer carrying a laminated first edition of the Bomber Traverse Map to the Snowbird Hut, August 2017.

Notes on Mountain and Place Names

Ordered alphabetically; click to open.

Donations from Map Sales

A portion of every Bomber Traverse Map sale is donated to the organizations that maintain the huts.

Donation History

$1675 – Mountaineering Club of Alaska, November 2020
$425 – Mountaineering Club of Alaska, July 2022