Ice Navigation: Every Voyage is Different

It’s late in the season so Captain Duke Snider, sailing on a resupply voyage from New Zealand to Antarctica, is expecting virtually no sea, just glacial ice.

Snider has been an ice navigator for decades, and he has seen the ocean change, not just here in the polar south, but in Arctic waters as well.

“Variability is much greater than in the past when we could expect an ice breakup to occur within a calendar week, year after year, whether it was the Arctic or the Antarctic,” he says. “Now, you have to look at each year individually and be more alert than ever before, particularly with lower ice class or non ice class vessels.”

He notes the rule-of-thumb from past decades where ships planned to be out of the Arctic by September 28. Now, low ice class vessels are operating until November. “Then, all of a sudden, the situation returns to the historic norm for a season, and inexperienced operators are caught by surprise.”

Warmer average temperatures and the corresponding loss of sea ice is allowing glaciers to move more quickly across the land and then calve more readily when they reach the sea. That means more glacial ice,