An armada of about 100 icebergs was just a few hundred kilometers from South Iland last night, prompting warnings for shipping and raising the remote prospect of the first iceberg sighting from the mainland in decades.

The surprised Whenuapai-based crew of an Air Force Orion, on a routine southern patrol looking for illegal fishing, spotted the first of the icebergs about 260km south of Invercargill late yesterday morning.

The frigid flotilla was split into two groups of about 50 icebergs. One group stretched about 185km south, and the other was concentrated in a chunky, icy mass about 37km wide.

Air Force spokesman Squadron leader Glenn Davis said the largest iceberg was about 1.8km long, 1.3km wide, and towered about 120m above the choppy waters. Given 90 percent of an iceberg is underwater, that meant the largest was 1.2km high.

The icebergs were north-east of the Auckland Islands and south-east of Stewart Island, and were drifting slowly towards south-east New Zealand, Squadron Leader Davis said.

"It is not unexpected to see icebergs at this time of year, but the crew were slightly surprised to see them where they are now," Squadron Leader Davis said.

Niwa marine physicist Dr Mike Williams said some of the new icebergs sounded big enough to survive another week of their journey toward the east coast.
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But they were probably riddled with holes, and should collapse to close to the waterline.

"We'd need a bit of good luck, but if these `bergs don't melt too much then who knows, with favourable currents and wind, they might even get close enough to be seen from the mainland, "Dr Williams said.

They might be from the Ross Sea or Prydz Bay ice shelfs, and were most likely carried north by the current and a consistent pattern of southerly winds.

They might also have been part of one or two megabergs, which disintegrated as they drifted slowly through warmer waters.

It was a "very cool thing, if you'll excuse the pun" for the scientific community but it would be hard to tie the icebergs' drift north to global warming, Dr Williams said.

"It's more likely that this is just part of the natural cycle of the ice, but this time sea and wind conditions have pushed pieces from a very big iceberg north," Dr Williams said.

"It is unusual, and it is exciting to be reminded the waters around New Zealand are part of a much bigger picture, but that's about as much as we can say for sure," Dr Williams said.

The fleet was the first spotted so close to New Zealand for decades.

They were seen as far north as the Chatham Islands in the late 1800s, and were last seen from the mainland in 1931, from a beach near Dunedin, Dr Williams said.

Dr Williams did not have enough information to chart their speed or course last night.

Maritime New Zealand yesterday issued a navigation warning to what was last night an unknown number of boats southeast of Stewart Island.

A much smaller scale warning was issued for the same area on October 17, and again in January

http://www.stuff.co.nz/stuff/0,2106,3849683a7693,00.html

04 November 2006
By STU OLDHAM