New Zealand's glaciers

Massive ice chunks split off from glacier

By AL WILLIAMS - The Timaru Herald | 5:00AM - Monday, 23 August 2010

GLACIAL EVENT: Thirty to fifty million tonnes of ice
have broken off the Tasman Glacier forming around
twenty icebergs now floating in the Tasman Lake.

A LARGE SECTION OF ICE, estimated to weigh 30 million tonnes, has broken off the Tasman Glacier, resulting in a number of icebergs entering the lake.

Heavy rain in the Aoraki/Mount Cook National Park had caused the glacier's terminal face to tilt and lift up, signalling a fresh round of dramatic calving activity at the weekend.

Discovery Tours chief guide Vernon Reid, who had been watching events unfold, said he had never seen such a large amount of ice and calving activity on the Tasman Glacier in winter in the 18 years he had been in the Aoraki/Mount Cook region.

Mr Reid said he believed the unusual winter activity of ice breaking up was due to the ever-increasing volume of the Tasman Glacier's terminal lake. "We may see an increase of such large-scale ice-calving events."

Aoraki/Mount Cook Alpine Village Ltd tourism general manager Denis Callesen said it was the biggest calving yet.

"Certainly everything above the water has gone. Based on my calculations, around 30 million tonnes."

A team from Glacier Explorers, which gives tours of the terminal lake, managed to get close to the ice floe last week following heavy rain and avalanche threats.

Heavy rain in the region had seeped underneath the base of the glacier, pushing up the terminal base by 30 metres.

"It has been exciting and fascinating for both our guides and clients to witness these dramatic events unfold over the past two months from high on our tour viewpoint, which is directly above the terminal ice face," Mr Reid said. "This was also the first time in 18 years where the lake surface didn't freeze, just the lower section of the lake froze and the water in the terminal lake looked a very blue hue rather than the common muddy colour."

He said guides now had a clear point of view, enabling them to see the glacier's calving activity including the entire lower 12km surface of the glacier, the thermokarst lakes, moraine-covered surface and ever-increasing ice cracks, giving people the opportunity to truly appreciate the glacier's rapid retreat.

"When I first arrived in 1992, the Tasman Glacier was around 29km in length. Today it is around 25km long and will continue to retreat until a new equilibrium is reached.

"There are now a number of complex processes which influence whether a glacier advances or retreats but, for now, the Tasman Glacier terminal lake is the biggest single factor and many exciting changes will occur in the next few years."

A chunk of ice — about 250m long, 250m wide and 80m high — fell into the terminal lake in February last year, generating a 3m surge of water.

http://www.stuff.co.nz/timaru-herald/news/4049150/Massive-ice-chunks-split-off-from-glacier

Glacier calving changes landscape

The Press | 2:19PM - Monday, 23 August 2010

BEFORE: The terminal face of the Tasman Glacier prior to the huge break-off of ice.

AFTER: Thirty to fifty million tonnes of ice have broken off the Tasman Glacier.

THIRTY TO FIFTY MILLION TONNES OF ICE have broken off the Tasman Glacier forming around 20 icebergs now floating in the Tasman Lake — adding more drama and spectacle to an already dramatic landscape.

The process began earlier this month when the terminal face rose 20 to 40 metres thanks to a rain downpour which lifted millions of tonnes of ice from the water across the entire 600m width of the face.

On August 18, a small section of that ice calved resulting in a massive and spectacular iceberg separating from the face. Sometime over the weekend, the rest of the uplifted ice broke away from the terminal face in the biggest ever calving in the lake's 35 year history.

Glacier Explorers, which takes passengers on cruises on the Tasman Glacier Terminal Lake, will resume operations on 03 September, one month ahead of schedule due to an early spring melt and to take advantage of the opportunity to see the magnificent new icebergs.

Denis Callesen, General Manager Tourism for Aoraki Mount Cook Alpine Village Ltd said the coming season promises visitors the most spectacular iceberg and glacier cruising season yet.

"The scale of what's happening here is just enormous. The biggest iceberg is about 300m by 200m and 40m high — and that's only the 10% of the 'berg that we can see. Ninety percent is below the waterline."

Callesen said the Tasman Lake is now full of icebergs with more than 20 that are 50m by 50m above the waterline.

"These 'bergs now take on a life of their own, flipping, turning and moving as natural forces take action."

Callesen said he and Glacier Explorers staff were "incredibly excited' about the coming season.

"We are expecting the most spectacular season ever here, with stunning viewing of nature in action. Visitors will be able to get out onto the lake from early September and they will be in for a trip of a lifetime with sensational iceberg viewing. The current calving will give us ice to study for the next two seasons at least."

The season will open with two trips a day increasing to five as the season develops.

http://www.stuff.co.nz/the-press/news/south-island/4051422/Glacier-calving-changes-landscape

• More photographs at: The Hermitage Hotel and Glacier Explorers Facebook pages.