Heavy sea ice off Alaska's north coast keeps shipping routes shut

Sea ice off Alaska's north coast is at its heaviest in more than two decades — and it's keeping the Arctic's shipping lanes shut.

At the end of July, ice in the Chukchi Sea ran higher than in any year since 2000, and the Beaufort Sea reached its heaviest end-of-July level since 2003, according to National Snow and Ice Data Center analysis in climate specialist Rick Thoman's Alaska and Arctic Climate Newsletter. The ice around Alaska, Thoman wrote, "looks like it's taken from the 1990s."

That matters most for supply lines. Both far-north shipping routes — the Northern Sea Route along Russia and the Northwest Passage through Canada — remain blocked to vessels without ice strengthening. And heavy coastal ice complicates the short summer window when barges deliver fuel and bulk goods to Alaska's remote Arctic communities, which have no road access and depend on the sea to resupply.

The heavy ice is a regional story. Across the Arctic as a whole, extent is well below normal, and near record lows on the Atlantic side, where ice from the Greenland Sea to the Kara Sea is 30 percent under last year's July record low. But in Alaska's waters the ice has held on, a pattern building since late June.

Melt continues into September.