ORONO, Maine — Bert Yankielun has built several hundred igloos in the last 20 years, but after getting a close look at a cake of snow on the University of Maine Mall, he wasn’t sure the igloo he hoped to build Wednesday afternoon would stand.

The first few slices, it seemed, weren’t holding in slabs.

“This is the part that always makes me nervous, if the snow is an appropriate consistency for the project,” Yankielun said as he sawed into the powdery snow cake. “It looks like we’re not going to have ideal snow to work with.”

But as Yankielun and dozens of students who gathered to watch and help with the igloo-building process began to cut deeper and deeper into the snow cake, he began to see possibilities.

Toward the middle of the cake, the snow was packed much tighter. The igloo would work after all.

Engineer, inventor, author and explorer Yankielun was on campus at the invitation of the Foster Student Innovation Center and its coordinator, Jesse Moriarty.

The immediate goal of the igloo-building exercise was to demonstrate the process. The long-term goal, Moriarty said, was to inspire the Foster center students and get the word out about the center, which helps students turn ideas into real-life opportunities.

The recently retired Yankielun has plenty of experience living in subzero temperatures. He was an electrical engineer for the Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory in Hanover, N.H., and has made trips to the Arctic and Antarctic. He holds patents on several radar instruments, consults for the Coast Guard, and sea kayaks in his spare time.

He also wrote the book “How to Build an Igloo and Other Snow Shelters.”

Moriarty said Yankielun, who recently moved to Deer Isle, came to the center’s attention thanks to Perry Hunter, a 1952 UMaine graduate who has been a supporter of the center and lives in Stonington, the neighboring town to Deer Isle.

Wednesday’s igloo-building process started when Yankielun asked a student to make a snow angel on the ground to determine the approximate size of the igloo.

He then cut into the snow cake, which was built and compacted by Moriarty and others involved in the Foster center. Once he found areas that were packed solidly, Yankielun and his volunteers set 2-by-1-foot blocks of snow into a circle, with Yankielun shaving and sawing the sides so the blocks would fit snugly against one another.

Yankielun then revealed the secret to a good igloo. He shaved off the tops of the blocks, tapering the snow on top to face inward, to form a sort of vertical spiral ramp. The idea, he said, is that each block will be shoulder-to-shoulder and have two points of contact with the neighboring block, so that the blocks lean on and support each other at the same time, and eventually form what Yankielun called a parabolic dome.

“If you just put another layer on top, on top, on top, the structure wouldn’t work,” he said. “It would be fairly unstable.”

While one group continued to build up the igloo, more students worked on a quinzhee, which is a hollowed-out mound of snow. Others constructed a shelter out of the leftover igloo blocks which Yankielun used to demonstrate how even a quick, crude wall of snow blocks can be enough to survive.

As the students learned, however, building an igloo in Maine takes some planning. New England snow isn’t optimal for igloos, because it needs to be cold and windblown, and the region’s climate is such that snow undergoes a thaw during the day. That’s why the pre-packed snow cake was key.

Sophomores Christina Hassett of Yarmouth and James Humenansky of Pennsylvania were among the students who helped cut blocks of snow.

“We want to go camping in Acadia National Park and build an igloo,” Humenansky said. “When else are you ever going to learn how to do this?”

After the demonstration, Yankielun and the rest of the group warmed up in Memorial Union, where he gave an informal talk about invention and creativity.

The timing of Yankielun’s presentation worked well with Winter Carnival, which will include an igloo-building contest on the UMaine Mall. The carnival is held Feb. 13-15 in conjunction with Family and Friends Weekend.

Igloo-building is an ideal winter activity, Yankielun said, because there’s no cost to it, aside from a few shovels and a cheap saw, and it gets people into the outdoors. There’s a team-building aspect to it, too.

“You see these people?” he said as he watched students working on the igloo with Hunter. “I don’t know how many of them knew each other before, but you see a bunch of people working together with a strange material and with a little instruction and a lot of teamwork, the next thing you know, they’re building something together.”

The Foster Student Innovation Center will post Yankielun’s igloo-building instructions at www.umaine.edu/innovation. For more information about Yankielun, go to www.doctorwhy.com