WELLINGTON, New Zealand - A flotilla of hundreds of icebergs that split off Antarctic ice shelves is drifting toward New Zealand and could pose a risk to ships in the south Pacific Ocean, officials said yesterday.
The nearest one, measuring about 30 yards high, was 160 miles southeast of New Zealand’s Stewart Island, Australian glaciologist Neal Young said. He couldn’t say how many icebergs in total were roaming the Pacific, but he counted 130 in one satellite image alone and 100 in another.
Large numbers of icebergs last floated close to New Zealand in 2006, when some were visible from the coastline, the first such sighting since 1931.
Maritime officials have issued navigation warnings for the area south of the country.
“It’s an alert to shipping to be aware these potential hazards are around and to be on the lookout for them,’’ said Sophie Hazelhurst, a spokeswoman for Maritime New Zealand.
No major shipping lanes or fishing grounds are in the area, but most ships there have little hull protection if they collide with an iceberg, which typically has 90 percent of its mass under water. Very few adventure sailors would be in the waters in November, when it is still the southern hemisphere’s spring.
Icebergs are routinely sloughed off as part of the natural development of ice shelves, but Young said the rate appeared to be increasing as a result of regional warming in Antarctica.
“Whole ice shelves have broken up,’’ he said, as temperatures have risen in Antarctica, where they are up as much as 5 degrees Fahrenheit in the past 60 years.
But he cautioned against linking the appearance of the icebergs in New Zealand waters to global warming: The phenomenon depends as much on weather patterns and ocean currents as on the rate at which icebergs are calving off Antarctic ice shelves.
In the current case, a cold snap around southern New Zealand and favorable ocean currents conspired to push the icebergs, which have drifted around Antarctica for the past nine years, to the region intact.
