The Southern Alps, Mount Cook, and the Nor’westers

Mount Hood Hiking Path

Students of New Zealand wine are familiar with the mountain range known as The Southern Alps. They can probably tell you that the mountain range extends along much of the length of New Zealand’s South Island, forming a rain shadow that keeps a good portion of the eastern side of the island warm and dry. For this reason, the wine regions of Marlborough, Canterbury, and Central Otago are able to grow some of the finest Sauvignon Blanc, Chardonnay, and Pinot Noir in the world.

The Southern Alps run for about 275 miles, forming a natural dividing range along the entire length of the South Island. New Zealanders often refer to the range as the Main Divide, as it separates the more heavily populated eastern side of the island from the somewhat wilder west coast. A large portion of the mountain range, which includes glaciers, glacial valleys, and lakes, is inaccessible except to the heartiest of mountaineers, and enjoys the protection of the National Park Service.

The highest peak in New Zealand, Mount Cook (also known by the Maori name “Aoraki,” said to mean “Cloud-Piercer”) is part of the Southern Alps.  At 12,218 feet high, Mount Cook is a dangerous but popular challenge for mountain climbers.  Aoraki/Mount Cook consists of three summits – the Low Peak, the Middle Peak, and the High Peak – surrounded by the Tasman Glacier to the east and the Hooker Glacier to the west.  The settlement of Mount Cook Village is a tourist center and serves as a base camp for climbers. For the adventurous, the area offers a wealth of hiking and skiing as well as star-gazing at Mount John Observatory in the Aoraki Mackenzie International Dark Sky Reserve – the largest dark sky reserve area in the world.

Nor’west Arch over Canterbury Photo by Jman Matthews

The prevailing westerly winds known as the “roaring forties” push in from across the Southern Ocean and the Tasman Sea, bringing along with them a host of moist air, much of it aimed directly at the west coast of New Zealand. When the winds bump up against the mountains of the Southern Alps, they are forced upward, and this force cools the air, and condenses the moisture to rain. The cold air and precipitation are kept on the west side of the island, thus creating the warmer, drier conditions on the eastern side of the island where the majority of the population (and vineyards) live.

The prevailing west winds also create a weather pattern known as the nor’wester. As the ocean breezes rise up the west side of the mountains and drop their rain, the wind turns warm and dry as it descends down the eastern side of the mountains, similar to the Zonda often experienced in Mendoza. These warm, dry winds play a major role in the intermittent droughts experienced by Canterbury and other regions on New Zealand’s eastern coasts.

A more pleasant side effect of the nor’wester winds is a cloud formation unique to the South Island of New Zealand known as a “nor’west arch.” A nor’west arch appears in the sky as an arch of cloud in an otherwise blue sky, and is frequently visible in the summer across Canterbury and North Otago.

The Bubbly Professor is “Miss Jane” Nickles of Austin, Texas

Context is Queen: I know this post seems a bit far-fetched for a wine post…but…I’ve found in teaching or studying a subject as complex as wine, it helps to know the context. While a wine student may memorize the fact that the Southern Alps form a rain shadow for parts of New Zealand, taken out of context, that bit of information will remain what students (not so kindly) call a “factoid” and others may call “trivia.” Such things are hard to remember, and even more difficult to understand. However, with a bit of context, especially at the human level (“what can you do there, do I want to go there, that looks cool/scary/weird…”) these facts become much easier to remember, use, and understand. So that’s what this post is all about – content is king, and context is queen!