Franz Josef Glacier
Where is the Franz Josef Glacier?
The Franz Josef Glacier is located in South Westland, on the West Coast of New Zealand at 43.5 degrees south, equivalent in latitude to the south of France. It’s an unusual place to find a glacier! There are no glaciers that extend down to sea level in France, so why does it happen here?
One of Only 3 Glaciers in a Rainforest
Descending to just 250m (820ft) above sea level, Franz Josef Glacier is one of only three glaciers in the world that descend into a temperate rainforest zone, the others being Fox Glacier (just south of Franz Josef Glacier) and the Perito Merino Glacier in Argentina (that we visit on our Condor trip). Franz Josef Glacier is steeper and faster moving than Fox Glacier, but like many glaciers worldwide, it is also retreating. The glacier is still rocketing down the valley, but the melting at the front, or terminal face, is faster than the ice is descending. Let’s figure out how all this works…
Literally running through Franz Josef is the Alpine Fault, which is the join where two tectonic plates collide - you can read more about it on our Geology of New Zealand page. The plate on the east side of the join (the Pacific Plate) is being pushed up and past the plate on the west side (the Indo-Australian plate) and this movement is what has formed the Southern Alps. In fact, the Southern Alps are still growing, at about 5mm a year! Being one of the youngest and fastest-growing mountain chains in the world, the result has been the creation of dramatically steep mountains as high as 3,700m (12,300ft), within 40km (25 miles) of the coast.
Why the Glacier Hasn’t Melted, Yet?
Now, have you ever heard of the ‘Roaring Forties’? These are a system of winds and weather patterns that circle the bottom part of the globe continuously, and relentlessly – they pretty much have nothing in their way, except Patagonia, a few hungry albatrosses and… the Southern Alps. When the moist ‘Roaring Forties’ wind hits the Alps, it gets forced upward very quickly and then dumps enormous amounts of moisture in the form of rain down low, or snow up top. On average, the upper Franz Josef Glacier gets almost 14m (45ft) of snow every year! The upper catchment area, or nevé, of the Franz Josef Glacier is about 20km2, so it’s a pretty big area for snow to accumulate. Eventually, that snow gets buried by more snow and then compacts and turns to ice, and because the valley is so narrow and steep and has an enormous amount of ice in the nevé, the glacier begins to flow under its own weight (imagine squeezing a tube of toothpaste, the tube being the valley walls and the paste being the glacier).
The other factor that contributes to the glacier being able to make it to almost sea level without melting is, again, rainfall. Because there is so much rainfall, water is constantly on, under and around the lower part of the glacier. This acts as a kind of lubricant, enabling the glacier to accelerate to great speeds (for a glacier!). So, the glacier is descending down the valley faster than it can melt. The rate of flow varies depending how high you are on the glacier - up top where there is greater pressure, it can reach speeds of 1m (about 3ft) per day, while down the bottom where the pressure is less, it “crawls” along at 30cm (1ft) a day.
We’ve had little snow over recent winters and the catchment area has not been “topped up” very quickly, thus the weight and pressure up top has reduced, which, in turn, slows down the movement of the ice below. The melting, however, continues at a pretty steady rate, so the glacier goes into a retreat - the melt rate is faster than the flow rate. All make sense? Good, because there’ll be a quiz during one of our trips… just kidding… maybe ;)
Hardy West Coasters
Now, you’re probably thinking to yourself “with 6m (20ft) of rain a year, Franz Josef township, might be, well, a bit ‘drizzly.’” Indeed it can be, and the locals have a love-hate relationship with the rain, because without it, they wouldn’t have a glacier or beautiful rainforest right in their backyard. There are, however, a lot of other positives, like gushing waterfalls, glacier views, a unique guiding-history and, of course, the glacier is just “a stone’s throw” away from the town. It has bred a hardy bunch of people who look past the elements and have a real passion for the environment they live in. So, when on one of our trips, cruise up to a local “West Coaster” in Franz (as it is affectionately known) and ask them about the weather – it’s sure to break the “ice”… and you might also find out what “liquid sunshine” is.