CHEBOYGAN, MICHIGAN – From the bridge of the Coast Guard cutter Mackinaw, northern Lake Huron looks like a vast, snow-covered field dotted with ice slabs as big as boulders — a battleground for the icebreaker’s 58-member crew during one of the roughest winters in memory.
It has been so bitterly cold for so long in the upper Midwest that the Great Lakes are almost completely covered with ice. The last time they came this close was in 1994, when 94 percent of the lakes’ surface was frozen.
As of Friday, ice cover extended across 88 percent, according to the U.S. government’s Great Lakes Environmental Research Laboratory in Ann Arbor, Michigan.
Sections of the lakes, which hold nearly one-fifth of the freshwater on the world’s surface, harden almost every winter. That freezing keeps the Coast Guard’s fleet of nine icebreakers busy clearing paths for vessels hauling essential cargo such as heating oil, salt and coal. But over the past four decades, the average ice cover has receded 70 percent, scientists say, probably in part because of climate change.
Still, short-term weather patterns can trump multiyear trends. Winter arrived early and with a vengeance and refuses to loosen its grip.
“That arctic vortex came down, and the ice just kept going,” said George Leshkevich, a scientist with the federal lab.
The deep freeze is more than a novelty. By limiting evaporation, it may help replenish lake water levels — a process that began last year after a record-breaking slump dating to the late 1990s. Also getting relief are cities along the lakes that have been pummeled with lake-effect snow, which happens when cold air masses suck up moisture from open waters and dump it over land.
Heavy ice can protect fish eggs from predators, and it also has delighted photographers, ice anglers and daredevil snowmobilers.
At Apostle Islands National Lakeshore in Wisconsin, the rock-solid cover has allowed around 35,000 visitors to trudge for kilometers over Lake Superior to explore caves featuring dazzling ice formations. It is the first time in five years the lake surface has been firm enough to allow passage.
Icicles by the millions dangle from the cave ceilings like giant chandeliers, many as delicate and as sharp as needles, others so intricate they appear to have been carved by a master craftsman. Waterfalls frozen into towering pillars extend from cliffs to the lake shore.
With no letup in the cold, the ice has not experienced the usual thaw-and-freeze cycle that causes blurring, so nature’s artistry is even more delicate and beautiful, with needle-like hoarfrost crystals sprinkled across sheets that dangle from cave ceilings like giant chandeliers.
“Seeing them like this is almost a once-in-a-lifetime experience,” Superintendent Bob Krumenaker said.