SANDSTONE, MINN. — A variety of soft thunks can be heard in between hollers of encouragement as more than a dozen climbers — mostly college-aged — take on a giant wall of ice for the first time.

They tip their helmeted heads to stare up the rippling formations that look gray or white in the shade, but glow with blues and yellows when the sun shines on Sandstone's Robinson Quarry, also known as the Robinson or Sandstone Ice Park.

It takes practice to "read" the ice and gauge the most stable spot to thrust in spiked crampons attached to sturdy boots. Thunk. Then there's the higher pitched sound of an ice ax picked into the ice. It helps to have a good ear, too.

"When you get a good stick, it's going to sound different," coached Bryan Karban of Vertical Endeavors, who was leading this group of novices a couple weekends ago. "It's all in the flick of the wrist," he continued. "And learning to trust your feet is the biggest challenge."

Ice climbing requires balance, plus skills in transferring weight, choosing good ice and leveraging strength while simultaneously being aware of how winter affects the muscles. If you keep your arms continually elevated during a climb in cold temperatures, it's going to be a wicked rush of blood when you finally bring your arms down. Karban said climbers have dubbed that experience "the screaming barfies" for the urge to throw up from the pain.

Safety is essential — including gear such as helmets to protect against falling ice or falling gear. It's one of many reasons to learn this tricky sport from the experts.

Given the cost of ice-climbing equipment — which can easily run upward of $1,000 for boots, crampons, axes and ropes, webbing and harnesses — it's doubly wise to try ice climbing first with a guide or an outfitter. An even better way to get introduced to the sport comes next weekend with the 10th annual Sandstone Ice Festival.

Both beginners and experienced climbers will have the opportunity to test out equipment while participating in a variety of ice-climbing clinics and talks. It's also a good chance to learn about winter camping.

Cascades of ice

Sandstone's community of 2,775 residents 90 miles north of the Twin Cities found its tourism niche as a hot spot for climbers — the climbers discovered the town's cliffs and nearby bouldering more than a decade ago.

Some of these climbers didn't want to hang up their ropes when the first snowflakes flew. So they started testing their skills on a few natural ice formations. Water from a swampy area above the cliffs of Robinson Quarry would seep down and form giant stalactites if temperatures were cold enough.

The cliffs were sculpted decades ago by excavators on this former quarry site. They average 60 feet tall but can reach heights of 70 feet. When the Ice Fest began a decade ago, and Mother Nature wasn't feeling cooperative, the city would occasionally help out and offer firetrucks with hoses to supplement ice formations. By 2010, the city approved a Sandstone Ice Park with pipes and a hydrant to flood the cliffs.

"Now we farm ice," said Sam Griffith, Sandstone city administrator and clerk. "We can guarantee there will be ice."

The new plumbing doubled the amount of climbable ice and gave climbers the ability to add more challenging routes for Minnesota's increasingly talented pool of ice climbers, said Jeff Engel, a Twin Cities climber and volunteer who's assumed the role of chief engineer and ice architect.

And while the park won't put Minnesota on par with the nation's top ice parks such as Ouray, Colo., the cliffs rippling with ice have become a Midwest destination.

For many Sandstone residents, it's been a surprise to watch the quarry spike in popularity. This quarry, which is on the National Register of Historic Places and was the reason for the town's formation in the 1880s, has always been known more for scenic walks or a place to picnic and take senior photos. Now climbers from Fargo, Chicago and Des Moines are finding their way here.

"Hopefully they'll have a good experience and come back," Griffith said.

Chances of that are good, especially with summer climbing options expanding into nearby Banning State Park and some possible bouldering areas across the Kettle River from the ice park. And there's a new cool factor coming to Robinson Quarry this winter: colored LED lights frozen into the ice to illuminate it for night climbing.

Even without the bling of night lights, the daytime ice offers an otherworldly diversion for visitors who do little more than stand back and watch as climbers in a rainbow of outerwear stick and pick their way to the top.

Jessica Daignault, a rock climber and St. Paul transplant from Michigan's Upper Peninsula, was familiar with natural ice climbing from her home state. She seemed eager for her first Minnesota ice-climbing experience during a recent Vertical Endeavors clinic at the park. Daignault made it about three-quarters of the way up before feeling she was losing strength. Once back on the ground, her arms felt on fire, but her enthusiasm stayed strong as she shook life back into her limbs and admired how natural the man-made formations looked.

"This is the best way to learn," said Zach Conklin, one of her instructors. "Throw yourself at the ice. You're not going to be awesome right away, but by your third or fourth climb, it will be vastly different."

Lisa Meyers McClintick is the author of "Day Trips from the Twin Cities." Find her at www.10000Likes.com.