Massive icebergs calve off Tasman Glacier
A pilot who flies over the Tasman Glacier up to five times a day, says the huge chunks of ice which broke off it this week are like something you’d expect to see in Antarctica.
Chris Rudge took photographs of the massive icebergs as he flew over yesterday and said they were ‘‘warehouse-sized’’.
Other photos were posted to Facebook by two guides from the area who were alerted to the event in the Aoraki/Mt Cook National Park early on Wednesday.
‘‘It’s normally places like the Antarctic or Alaska where you get that sort of break up,’’ Rudge said.
He said it was the biggest event he had seen on a lake in more than 10 years of commercial flying above glaciers.
Rudge, a former information officer for the New Zealand Antarctic Programme, has done eight trips to Antarctica.
‘‘It’s not the sort of thing you expect to see in New Zealand,’’ he said.
He thought the chunks would be some of the biggest in the country.
"For New Zealand, it’s pretty big. If you think about it, Tasman Lake is the largest glacial lake in New Zealand. It’s getting bigger year by year, and of course break offs emerging at this time of year has increased. But it’s a fairly big event even by local standards.
‘‘The bigger the lake gets, the bigger the break can technically be. I’d say it’s right up there with some of the biggest ever recorded.’’
The breaking of ice chunks from the edge of glaciers is known as glacial calving.
University of Canterbury glaciologist Heather Purdie said large calving events happened about once every two years on the Tasman Glacier.
They were caused by glacial ice above the water melting, putting pressure on the ice beneath it still under the water.
When the pressure became too much, the ice eventually snapped off.
‘‘What you’ve got to remember is that only one tenth of that iceberg is actually above the surface,’’ Rudge said.
‘‘They are massive.’’