1. The largest glacier is 600m thick and 29km long
The Tasman Glacier, Aoraki Mt Cook National Park, is New Zealand’s largest glacier both in length and in width. 22,000-16,000 years ago, it was joined by nearby Murchison, Hooker, and Mueller glaciers to create a mega glacier of 115km. The giant glacier is actually the source of the popular Lake Pukaki, which was carved over thousands of years of receding ice.
2. Two planes have been discovered inside glaciers
The Mangatoetoenui Glacier on Mt Ruapehu is moving at a generally slow speed of 20m a year, which has been calculated thanks to a plane crash that happened in 1952. The plane emerged 31 years later, time-locked in this slow-moving conveyor belt of ice, eventually bursting out of the front glacier wall. In a similar event, a plane crashed on Franz Joseph in 1943. When the plane emerged through the front face of the glacier only six years later, it showed the glacier to be moving at a speed of 600m a year.
3. New Zealand used to be one island because of the glaciers
During the Ice Age, sea levels around the country dropped suddenly. Water became locked in glaciers, exposing surrounding sea floors. New Zealand became a single large island as the Cook Strait dried out. Even Stewart Island was connected to the mainland. Essentially, New Zealand was a giant glacier!
4. Glaciers carry gold!
Ice Age glaciers are the reason gold was found in the river beds, streams and beaches. The gold was carried by glaciers down the mountain, the rivers and finally out to sea, turning the beaches into a shimmering shining shore which sparked the 1860’s West Coast and Otago gold rush!
5. Glaciers are the reason New Zealand’s rivers and lakes look like this…
The milky blue water flowing from the glacial melt is the result of finely ground rock that pigments the water. This pigment is called ârock flourâ. During the Ice Age, the wind picked up the rock flour from the South Islandâs inland glaciers and covered the Banks Peninsula, several hundred kilometres away, in metres of thick rock flour.
6. There are 18 glaciers on one volcano
As well as a glacier hidden away in the crater of Mt Ruapehu, the mountain has 17 other glaciers sourcing from its summit. The three largest glaciers are Whangaehu, Mangatoetoenui and the Summit Plateau. Walk the glaciers yourself by checking out How to Get to Mt Ruapehu’s Crater Lake in Winter.
7. Glacier crevices are so large they could hold buildings
Glacier snow can hide huge crevices so big that they could hold buildings within it. Glaciers start high up in the mountains sourced by many metres of snowfall, which compacts and thickens over the years turning it into ice. This forms the start of the glacier. As it descends through the mountain’s valley the weather attacks it over the years eating away at its surface to form cracks and crevices as deep as 60m. These can then become hidden by snow. Be careful if youâre ever walking on or near the sources of glaciers.
8. Rock glaciers: they exist!
Some arid mountains in the South Island can contain ârock glaciersâ. Rock glaciers are snow and loose rocks that are frozen together. At the centre of the rocks and between all the gaps, ice acts like glue sticking rocks together. The process is so vast that it gives the impression of a river of slow-moving rock.
9. Franz Josef and Fox Glacier cause flash floods
Franz Joseph and Fox Glacier, West Coast, have been the cause of flash flooding for thousands of years. Melted snow and rain gather in the gaps between the two mountain sides and slowly freeze. Liquid water remains trapped and will only be released when the parts of the glacier holding it back finally break. Then, it can surge to the bottom of the valley.
10. Franz Josef is set to shrink by 38% by 2100
Studies conducted in 2008 by glaciologists – yep, thatâs the name of the scientists studying the behaviour of glaciers – concluded that by the year 2100 Franz Joseph will have lost 38% of its mass. Global warming is a fact, people, so be a green backpacker!