This trip report describes the descent of a glacial-fed canyon with a grade of V6A6VI****. It is only 1 of 2 in NZ with this grade. It requires special techniques and a high level of skill to descend. It requires multiple days to approach, scout, descend, and return. Due to the nature of the canyon rescue could be impossible<\/strong>. This canyon should only be attempted by expert<\/strong> teams familiar with this style of descent.<\/p>\n\n\n\n Margaret Burn, affectionately known (only by us) as \u201cMargy B\u201d, is a canyon located along the Dart River in the South Island of New Zealand. It was originally scouted in 2024 and the lower section was descended on the same trip. The upper and middle sections of the canyon were not descended. This trip we planned to scout and link the remaining sections and do the first \u2018integral\u2019 descent (canyoner speak for descent of all sections).<\/p>\n\n\n\n Margaret Burn is unique as a majority of the canyon flows underground. Boulders have fallen into the canyon, wedged themselves against the walls and created a roof. Over time the forest has grown over the top. You can walk on top of the canyon in several sections. Beneath the roof is a world-class canyon which can only be seen by headtorch. <\/p>\n\n\n\n The canyon is fed by a glacier, meaning its water level can vary depending on season, weather, and even time of day. The heat of the day causes the glacier to melt, changing the water levels from passable, to deadly. To give us the best chance of completing the full descent we would go in April, meaning lower air temperatures and thus lower water levels.<\/p>\n\n\n\n The canyon is split into 3 distinct sections. The upper is an extremely narrow canyon, with twisting walls, extremely high flow, and big waterfalls. This is the only section that is 100% above ground. The middle section flows completely underground. It is best described as a cave rather than a canyon. The fallen rocks create unique hazards that take extreme care and delicate abseiling to traverse. The lower section begins with a 30 metre waterfall and then goes back underground. 80 metre tall walls are capped by the forest above, you walk and swim your way through before emerging into the sunlight, and the junction with the Dart River.<\/p>\n\n\n\n All good canyoning stories start in Empress right? I find myself at the change spot, and instead of changing into my usual neoprene, I'm putting on a bright red drysuit. Looking like a power ranger I jump into the first pool. The feeling is odd. I'm completely dry. Margy B is fed by a glacier and melting ice is cold (duh). In these conditions wetsuits just don't cut it, so our team will be using drysuits for warmth. Since I'm the only one who hasn't used one before, a quick empress run was in order to test it out. Confident it works as intended (and doesn't clash with my colour scheme) I head home and finish packing. <\/p>\n\n\n\n Thankfully a similar trip to Taiwan in January meant I already had my packing list written down. Some minor tweaks (and last minute shopping) and I was ready to go. For my list of personal gear I took into the canyon have a look at my lighterpack.com<\/a><\/p>\n\n\n![\"\"](\"https:\/\/unswoc.org\/wordpress\/wp-content\/uploads\/2026\/06\/661728966_4387597101510473_3853822043334950270_n.jpg\")
<\/a><\/span>Preamble<\/span><\/h3>\n\n\n\n
<\/span>Preparation <\/span><\/h3>\n\n\n\n
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