ST. JOHN'S, N.L. -

The greatest iceberg season in recent memory is drawing scores of visitors to Newfoundland's northern peninsula for a glimpse of the majestic sculptures.

"For this time of year, I've never seen so many icebergs -- and so big," said Paul Alcock of Northland Discovery Boat Tours in St. Anthony, N.L.

"It's a pretty spectacular sight out here right now," he said of at least 25 icebergs still looming within 16 kilometres of the town.

"For this time of year, you wouldn't expect to see much more than three or four."

The rare extravaganza is thanks to a nearby ice island that was part of a 260-square-kilometre chunk that split from Greenland's Petermann Glacier last August. That original piece has since broken into smaller bits.

One of the largest remaining pieces is the 50-square-kilometre ice island now floating about 20 kilometres off Labrador, south of Cartwright.

As it moves through the water, it "calves" or sheds pieces of ice that create the clusters of icebergs now attracting visitors from across Canada and parts of the U.S., Alcock said.

One of the highlights of his tour is a massive tabular slab that's about 1.6 kilometres long and 54 metres high.

"You've got waterfalls, you've got thick blue lines in the ice, you've got seals that are up on different places. It's almost like its own little habitat by itself. It's pretty amazing to see."

There's so much big ice that Alcock expects a record-long viewing season stretching into September.

"We had a gentleman a couple of days ago that got here from Montreal," Alcock said. "When he heard about it, that was it, he took a few days off work and made a beeline for Newfoundland to see them.

"People are left speechless."

Sara Weitkamp, a marine science technician with the U.S. Coast Guard, flew over the ice island Tuesday as part of the International Ice Patrol. She has completed 19 other similar missions.

"It's definitely the biggest piece of ice I've seen in my history of patrolling over the ocean," she said in an interview.

"There's a bunch of melt ponds and rivers that have started on it, just from the deterioration of it.

"It's amazing to think that something that big has lasted that long, down in an area that we patrol where we're used to seeing much smaller icebergs."

Charles Randell is president and CEO of C-Core, an engineering research and development corporation based at Memorial University of Newfoundland. He described how researchers placed eight beacons on the ice island to monitor its location, while satellite technology captures detailed images.

Information is passed on to the Canadian Ice Service, offshore operators, shipping officials and the International Ice Patrol, created after an iceberg sank the Titanic in 1912.

The giant ice slab shrank in the last week from 54.5 square kilometres measured Monday -- almost as big as the island of Manhattan -- to 49.5 square kilometres on Friday.

Randell has never seen anything like it.

"There have been ice islands, they're not unprecedented," he said. "Back as far as the late 1800s, there's actually a hand-drawn sketch of one off of St. John's that was reported to be eight miles long."

The size of last year's calving event off the Petermann Glacier has sparked debate about the potential role of ocean warming and climate change.

Randell stressed that he's not a climatologist, but said glacier ice is always moving.

"It's the tongue of this glacier that extends out through the fjord," he explained. "After a while, it gets so long and so narrow that a piece just breaks off."

The sheer size of the 260-square-kilometre break has driven theories that warmer seas are speeding up glacial movement.

But there are competing schools of thought on climate change and its effect, Randell said.

"We have seen warming trends over the period that we have been taking measurements. There's a camp that will say these are part of the natural cycles of the earth -- we have had ice ages before, and we may see them again."

For his part, Alcock has mixed feelings about what he calls "floating symbols of global warming."

"I'm excited about having these ice islands here, but there's part of me that's sad too because this is more evidence of climate change."

Alcock is also concerned about the number of impromptu tours being offered by local residents in small vessels not governed by the safety regulations his tour boat follows.

In an emailed statement Friday, spokeswoman Michele Boriel of Fisheries and Oceans Canada said the Canadian Coast Guard does not monitor the regular movement of small boats or pleasure craft, and there are no restrictions on viewing icebergs.

"Coast guard reminds boaters to exercise safe boating practices and keep in mind that icebergs can be dangerous and roll over at any time."