Tuesday, 4 July 2017

Dry Valleys and Lake Vanda - wonderful Antarctica

'There is a place on earth that is so unlike anywhere else on earth that it has been used to test equipment intended for use on Mars.'

The Dry Valleys region of Antarctica is one of the world's most extreme deserts, but that's only the start.

A dry valley in the Transantarctic Range.

Dry Valleys, Southern Antarctica.
Coordinates: 77° 28′ S, 162° 31′ E

The Dry Valleys are located on the western coast of the Ross Sea.

The Dry Valleys in southern Victoria Land, 100 km west of McMurdo station, form the largest ice-free area in Antarctica (4800 km2). They are the most extreme cold desert anywhere on earth, where the mean annual temperature is between -14º C and -30º C, most frequently under -20º C, and reaching a record low -68º C.

The Dry Valleys are protected from the ice masses of the Polar Plateau by the Transantarctic Mountains. They force air flowing upwards so they lose their moisture; the valleys then are in a precipitation shadow (where snow and rain don't fall).

Bull Pass, a low passage north of Wright Valley that shows clearly the contrast between "normal" iced Antarctica and the Dry Valleys.

The mountains also prevent the flow of ice down the valleys from the East Antarctic Ice Sheet and finally, strong katabatic winds of up to 320 km/h blow down from the interior along with the low humidity causing the ice from the glaciers that do discharge into the valleys to evaporate.

Wright Valley, the largest of the main three valleys; at far, lake Vanda.

There are three large valleys, Taylor Valley, Wright Valley and Victoria Valley (the great Queen is everywhere!). Taylor Valley was first discovered during Scott's Discovery Expedition (named after the ship) in 1901-1904. It wasn't until the 1950's that further valleys and their extent were discovered from aerial photography.

Taylor Valley. The montain top glaciers drop down to the valley but they can't feed the bottom with ice or melt water - winds evaporate the tiniest humidity.

It's been 2000 million years at least without rain falling.

Glacier sliding down to Taylor Valley.

Unexpectedly, in all this dryness there are rivers flowing, yes! No lush vegetation though, and no fish, but beauty is there somehow. At least, humans are hundreds of miles away, that's already a bit of paradise... Mostly everywhere Man just ruins Nature.

Maybe the most impressive is Wright Valley, through which flows the river Onyx to feed Lake Vanda. These names even sound like Scy Fy !

River Onyx and Lake Vanda, in Wright Valley.

During austral summer, the lake partially melts. River Onyx (left) flows into Lake Vanda.

Lake Vanda is the largest of several lakes, at 5.6 km x 1.5 km at extremes, with a depth of 69 m, it has a smooth ice cover of around 4 m thick, in the summer a moat develops as the shore ice melts. Water comes from summer melting of nearby glaciers, once a balance occurs between water entering the lake and ice sublimation from the surface, leading to a fairly stable situation.

The rocks here are granites and gneisses. Loose gravel covers the ground.

Lake Vanda is a hypersaline lake with a salinity more than ten times that of the Dead Sea. Lake Vanda is also meromictic, which means that the deeper waters of the lake don't mix with the shallower waters. There are three distinct layers of water ranging in temperature from 23 °C on the bottom to the middle layer of 7 °C and the upper layer ranges from 4–6 °C .

As there is little or no snowfall in the Dry Valleys the ice on the surface of the lakes is exposed and can be quite beautiful, very hard and clear blue, often with inclusions of small air bubbles, radiating and crossed crack lines.

The lake is always covered by a thick iced transparent layer, some 3 to 4 m deep, except in December when austral summer causes some melting in the lake borders.

Some wind blown sand dust remained captured under ice surface.

Cracks, melt lines and bubbles.

Onyx River is the longest in Antarctica - 32 km ; strictly speaking it isn't a river but a seasonal meltwater stream fed by glaciers.

The Onyx River is a meltwater stream which flows westward through the Wright Valley from Wright Glacier, during the few months of the Antarctic summer. Despite being only 32 kilometres in length it is the longest in Antarctica.

Onyx River, Antarctica Dry Valleys
Coordinates: 77° 26′ S, 162° 45′ E

Onyx stream is formed in Summer from melting Wright Glacier and flows inland along the Wright Valley for 28 kilometers until it reaches Lake Vanda. Strangely, it flows inland, away from the sea, its water never reaching the ocean.

The Onyx typically flows for 6-8 weeks in, in some years it may never actually reach Lake Vanda while in others it may flood causing significant erosion to the valley floor.

The stream flow is quite variable - some years it doesn't even flow at all; some other years, overflow causes large floods. As the river flows it supports some algal (cyanobacteria) growth particularly in the wider and shallower areas.

The New Zealander Vanda Station, at the mouth of the river, was removed in 1995 as lake levels rose, and replaced by a shelter - Lake Vanda Hut - that is temporarily staffed in summer by 2-8 researchers (meteorology, sismology, hidrology...).

The New Zealander hut by the lake, bottom centre.

What a wondrous place! I could sit here and rest to die when time comes...

Sunday, 18 June 2017

Stewart Island, south of New Zealand, a warm, cozy, rewarding remoteness

Now and then I search for places in the south hemisphere that fill the least requisites for Ultima Thule - remote, isolated, something not-of-this-world, rather unknown and somehow fascinating, mainly accessed by sea.

It's not easy. Besides the international Antarctic Stations, I've already mentioned here the Kerguelen Islands, Hobart in Tasmania, Dunedin and Invercargill in the south of mainland New Zealand. Further south is Stewart Island. This is really a hard-worked post, it took several weeks to publish, so enjoy.

Stewart Island is far from the main routes, known only of newzealanders and mostly uninhabitated. So it will do ;) as a warm, cozy Ultima Thule, at a higher latitude then Hobart but lower then Ushuaia or Punta Arenas.

The first Europeans to sight the island were explorer Captain James Cook and his crew in 1770, from the Shetland and Orkney Islands. They started sealing, whaling, tin mining, merino sheep farming, fishing and logging. Activity went growing, seventeen mills sites existed on the island. The European name was later attributed in honour of William Stewart, first officer on the ship Pegasus, from Sydney, which sailed to the island in 1809 on a sealing expedition.

Stewart Island is short of 18 degrees to the south polar circle, not-so-remote then, but who ever has heard about ? It's like a New Zealand's small Tasmania, still far from Antarctica - in fact, the territory enjoys a warm Mediterranean climate and a forested land free of ice.The highest peak is Mount Anglem, which stands at 979 meters near the northern coast.

The island is roughly 25 by 40 miles in size, the third-largest island of New Zealand, and can be reached from South Island across Foveaux Strait.

Oban is the main settlement, located on Halfmoon Bay by the Paterson Inlet. It has aircraft connections with Invercargill and a ferry service to Bluff, on South Island.

The town was named as Oban in Scotland ( An t-Òban in Scottish Gaelic, meaning Little Bay), most likely due to the strong influence Scottish settlers had in the south of early colonial New Zealand.

Oban / Half Moon Bay

Coordinates: 46° 54′ S, 168°  E
Population:  ~ 400

The only town on the island, Oban lies at the head of Half Moon Bay. It's known for the hilltop red roofed church, and several restaurants serving fresh seafood. Great sand beaches can be found around, and Oban is also the departing point for hiking excursions around the island.

The town's profile: a church on the green hilltop overlooking the wharf and the ferry pier.

Rakiura Visitor Centre (left), close to the ferry pier.

The old presbyterian church peeking up among green foliage.

The town has developped around Halfmoon Bay and the ferry pier.

Presently the two bays are linked by urban area, as the town reached Golden Bay.

The ferry arriving, viewed from uphill.

And viewed from aboard.

The Visitor Terminal, at the ferry's pier, is the liveliest place in town, with its Wharfside Café.

Church Hill Restaurant

Church hill restaurant on Kamahi Road.

Uphill by he church, this is a gourmet restaurant with particular ambiance and the best views in town.

Downtown Oban:

An excursion from a cruise ship is in town.

On Main Street, the French Creperie and the Bunkhouse Theatre.

Bunkhouse Theatre, a cinema and theatre venue.

Movies and comedy all year through.

Also a Gift Shop.

And the General Store.

Downwards by the waterfront:

Four Square supermarket.

The South Sea Hotel

South Sea Hotel on the bay's central front, maybe the island's best offer for accommodation.

Another option is Bunkers Backpackers BBH, Argyle Street:

The Rakiura Museum

Rakiura Museum on Ayr Street.


Heritage Centre and Museum.

The Centre houses an extensive collection of  first settlers and shipping items and photographs from the island's early history: European, Maori, nautical, fishing, timber, milling and mining. It also houses an extensive collection of Stewart Island shells and crustacea.

The end of the day at Oban

Horseshoe Bay, a neighbouring bay north of Halfmoon:

A local joke tells this should be the "halfmoon" bay, not the other, because of its perfect shape.

The Coast and the Bush

Stewart Island is situated in a region of unpredictable weather; 275 is the yearly average days of rain and frequently strong westerlies attacking the rugged granite, bush-clad island.

Wild beaches: Mason Bay

On the remote and wild west coast of the island lies Mason Bay, a desolately beautiful 14 km crescent of sandy beach.

The Dunes at Mason Bay.

The dunes here stretch inland as far as 3 km and are an amazing example the original dune ecosystem

The historic hut at Mason Bay is refurbished and more comfortable.

Lonnekers Beach

North Rakiura
The North Rakiura Track and huts.

The circular  Rakiura Track is Stewart Island's most famous hike. Taking three days, the trail covers 36 kilometers. It's a gentle track, convenient for all.

The circuit follows open coastline, along exposed shores of windswept trees and brush, crossing the forested interior of the island and winding along sheltered shores, inlets, bays and mudflat. In its mid section, the track crosses steep hills covered in dense forest, with well-maintained and gravelled trails.

Rakiura National Park covers 80% of the island's total area, over 200 km of tramping trails, forests of native trees and low-growing sub-alpine shrubs and grasses.

Port Williams Hut. There are several huts to accomodate hikers along the trail.

In fact, the inner bush feels much more remote than the twenty minute flight on a small plane or hour-long passage on the often ferry might suggest.

Maori Bay suspended bridge.

Rakiura Track

The southernmost point in the island's central ridge is Mount Allen, at 2,460 feet. Sub-alpine habitat allows endemic flora to grow free; this rare buttercup is one of a number of plants found only on Stewart Island.

Mount Allen Buttercup (Ranunculus viridis).

Many other small islands lie around the coast. Notable among these are Ruapuke Island, in Foveaux Strait 20 miles northeast of Oban; Codfish Island, close to the northwest shore; and Big South Cape Island, off the southwestern tip.

Codfish Island, small but spectacular.

South Island saddleback (Philesturnus carunculatus), once almost extinct, has recovered to a population of about 700.

Sunset at Mason Bay...

and at Rakiura Bay.

And more: at Stewart Island, you can even watch auroras! Austral auroras, of course, pink or green like this one.

Southern lights at Halfmoon Bay.