Mount Ruapehu

Where it sits. Ruapehu is the highest point in the North Island at 2,797 metres and the bulk at the southern end of Tongariro National Park. Unlike the neat cone of Ngauruhoe to its north, Ruapehu is a broad, messy massif roughly 25 kilometres across, built up over at least 250,000 years from overlapping andesite flows and now carrying the only substantial glaciers in the North Island. Its three named high points — Tahurangi, Te Heuheu and Paretetaitonga — ring a summit plateau, and in the middle of that plateau sits Crater Lake, Te Wai ā-moe, a warm acidic lake that rises and falls with the volcano's temper. Three ski areas hang off the mountain: Whakapapa on the northern side, Tūroa on the southwest, and the small club-run Tukino field on the east.

A volcano with a body count. Ruapehu is active and its hazard is not the eruption but the lahar — a fast slurry of water, ash and rock let loose when Crater Lake spills. On Christmas Eve 1953 a lahar came down the Whangaehu River and destroyed the rail bridge at Tangiwai minutes before the Wellington-to-Auckland night express reached it. The locomotive and five carriages went into the river and 151 people died, the worst rail disaster in New Zealand history. Eruptions followed in 1969, 1975 and, most disruptively, in 1995 and 1996, when repeated explosive activity dumped ash across the plateau and shut the ski fields for two seasons. In 2007 a phreatic eruption injured a climber sheltering near the crater, and later that year the refilled lake breached its tephra dam — an event anticipated for years and managed by an engineered alarm and bund system that worked as designed, with no casualties. Crater Lake itself runs on a slow heating and cooling cycle, swinging between roughly 15 and 45 degrees Celsius over months as gas and heat rise through the vent beneath it; the water is strongly acidic and grey-green with suspended ash. Small glaciers — the Whangaehu, Mangatoetoenui and Summit Plateau ice — persist on the upper mountain, the only permanent ice in the North Island, and they are shrinking measurably decade on decade.

On screen. Because Ngauruhoe could not be filmed on, Ruapehu became the ground where Mordor was actually shot. The rock ribs above Iwikau Village on the Whakapapa side — the formation known as Meads Wall — played Emyn Muil in The Two Towers: the maze of black crags where Frodo and Sam lose their way and where Gollum ambushes them on the rock face. The prologue of The Fellowship of the Ring, the Battle of Dagorlad in which Isildur cuts the One Ring from Sauron's hand, was staged on the ash and boulder fields of the same ski area. The march of the army out of Minas Morgul was shot nearby. On the eastern side, the Tukino field is where Frodo, Sam and Gollum look down over the plain toward the Black Gate before deciding to go around it. On the southwestern flank, the tussock and rock at Tūroa stood in for the hidden bay below the secret door of Erebor in The Hobbit: The Desolation of Smaug. All of it was shot under strict conditions — scaffolding and matting laid over vegetation instead of earthworks — and nothing was left behind.

What you can do on it. Whakapapa is the largest ski area in New Zealand; its Sky Waka gondola, opened in 2019, climbs to the Knoll Ridge Chalet at about 2,020 metres and runs through summer as well, which makes the high alpine zone reachable without a climb. Tūroa has the longest lift-served vertical drop in the country and the highest sealed road approach in the North Island. In summer the mountain carries the six-day Round the Mountain track, the Crater Lake route from the top of the Whakapapa lifts (a serious alpine walk, not a stroll, requiring settled weather and awareness of volcanic alert levels), and shorter formed walks lower down from Whakapapa Village.

Getting there and timing. The northern approach is State Highway 48 to Whakapapa Village, then the ski field road to Iwikau Village at roughly 1,625 metres. The southern approach is the seventeen-kilometre Ohakune Mountain Road from Ōhakune up to the Tūroa base at about 1,600 metres. Both are sealed; both require chains in winter and are closed when conditions demand. The ski season typically runs July into October, though recent seasons have been short and unreliable. January to March gives the best high walking. Volcanic alert levels are published daily by GeoNet and access to the summit plateau closes when they rise, which is a real possibility in any given year rather than a theoretical one.