National Geographic Daily News
Sightseers look at icicles at the mouth of a sea cave of the Apostle Islands National Lakeshore of Lake Superior near Cornucopia, Wisconsin February 14, 2014.

A frozen Lake Superior allows sightseers to visit cliffside ice caves on foot.


Dan Vergano

National Geographic

Published February 19, 2014

Icicles glisten as throngs of visitors explore frozen sea caves, seen in the above February 14 picture.

The caves ring the cliffs of the Apostle Islands National Lakeshore on Lake Superior, which is now 94 percent iced over. "Make sure to bundle up and dress in layers," the park recommends to visitors.

"Personal sled dog trips can be made to the caves. Commercial sled dog trips are not allowed," the park notes, and horses are forbidden as well.

Frozen Footsteps to Ice Caves

A photo of sightseers trekking across a frozen expanse of Lake Superior, the world's largest freshwater lake.

This is not your typical beach trip. Frozen lake ice opens a bridge to visitors, shown here tromping away on their visit on February 15.

Cave visitors take a cold walk of three miles or more over the ice to explore cliffside sea caves draped in the mantle of winter. The ice caves haven't been accessible on foot since 2009, and the park reports throngs of visitors this winter, especially on weekends.

Look Out, Above!

A photo of sightseers crouch to avoid icicles in a sea cave on frozen Lake Superior.

Watch out where you walk in the ice caves. Here sightseers duck to dodge small icicles hanging from a cave roof, shown in this February 14 picture.

The caves formed from the action of lake waves on ancient sandstone cliffs that ring the park. In the summer, crashing waves make them inaccessible to visitors.

For now, the park's website warns folks that some of the bigger icicles weigh hundreds of pounds and might pose a threat: "There are large icicles and frozen waterfalls suspended from the top of the cliffs," says a park statement. "They might break off and come crashing down at the most inopportune moment."

Icicles Erupt on Cavern Ceiling

A photo of icicles and hoar frost formed on the ceiling of an ice cave by Lake Superior.

Winter splashes hoarfrost on the ceiling of the ice caves. The needles form when moisture in the air condenses and freezes.

The pink shades of the longer icicles arise from the cave's red sandstone. Ruddy sand grains slough off the cave walls as the icicles grow.

Getting a Grip on the Ice

A photo of a man tightening new crampons on his boots at the sea caves of the Apostle Islands National Lakeshore of Lake Superior.

Jeff Neddo of Eagle River, Wisconsin, tightens the crampons on his snow boots as he gets ready to visit the ice caves.

Spike footwear is always in fashion when visiting the ice caves. The park recommends: "The areas along the caves tend to be very icy. There is a well-worn path, but it is uneven—a ski pole for balance may be helpful."

A sled for pulling the kids might also help.

Frozen Wave Drapes Cave

A photo of a man looking at ice formations in a sea cave.

Surf's up! Frozen foam sprays from the roof of an ice cave, observed by Mike Rundle of Janesville, Wisconsin, in this February 15 picture.

Fair Warning to Ice Trekkers

A photo of a car on the ice road on Lake Superior.

Even in the heart of winter, lake ice is never guaranteed safe for travel. A trip on the lake ice comes with warnings, such as the one shown in this February 15 picture.

The Sea Caves Watch website offers advisories, and satellites show ice cover on Lake Superior, for anyone interested in the big picture.

Ice Transforms Cave Opening

A photo of a man looking through an opening with his dog Max Sightseers at the sea caves.

Even the dog packs a sweater on the trip to the ice caves. Both suitably dressed, Pete Miller of Minong, Wisconsin, and his dog Max peer through a cave opening.

Admiring an Ice Palace

A photo of sightseers looking at a frozen rock face along the Apostle Islands.

A wintry mantle hangs from the sea cliff walls at the Apostle Islands National Lakeshore, seen in this February 14 picture. The base of the ice wall glows pink because of red sandstone scraped from the cliffs.

Sunset Bathes Sea Cave Icicles

A photo of a woman photographing ice formations at sunset on a rock face of the Apostle Islands.

Sunset shines on the icicles adorning the cliffs at the Apostle Islands National Lakeshore, accentuating the sandstone entombed by winter.

Some 88 percent of the Great Lakes are covered with ice this winter, a silver lining for ice-skaters and ice fishermen in a severe winter.

Alice da Silva
Alice da Silva

A natureza é assombrosa está sempre a surpreender-nos com a sua beleza  incomparável e única!



Chudamani Akavaram
Chudamani Akavaram

The Nature's will and power to thrill can be seen in the magical beauty of the caves dressed in the beautiful shapes of ice and icicles as in this photograph.

Francine Brewin
Francine Brewin

I just love caves, Ice caves change every year and are nature's canvas.  Regular caves show a permanent picture created over millions of years.  Underwater caves are spectacular and are alive. 

Axel Peterman
Axel Peterman

I went there a few weeks ago. AMAZING!! MUST SEE!

Debbie Kobs
Debbie Kobs

Was able to see these last weekend! They are amazingly beautiful! But, if you decide to go, be prepared to walk quite a long way! Well, worth the walk though.

Dwayne LaGrou
Dwayne LaGrou

If you go to see this then you should also stop at Tahquamenon Falls and check it out. All of the tannins in the river water make for an unforgettable sight! The water falls freez over the top of the falls while the water continues to flow under it. It is absolutely breath taking and you will never forget it.


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