What’s topless, strapped with a thong, and liable to make part of your body numb?

It’s a pair of flip-flops being worn through the snow, of course.

Students and young people are spending more time slipping into the slabs of rubber or leather punched with a toe-strap, as opposed to lacing up a cumbersome shoe. This has caused the market for flip-flops to explode in the past five years, industry experts say.

The sandals, once reserved for a day at the beach, are increasingly worn throughout the winter. Meanwhile, students accustomed to flip-flops balk at the thought of bending over to tie shoelaces.

Most of the University’s feet are protected from the January snowstorms by boots, sneakers, or dress shoes, though a few brave people, including third-year in the College Yesha Sutaria, allow their toes to defy the blustery cold.

“If the sidewalks have been cleared and the snow is off to the side, I’ll just slip them on and run out the door,” Sutaria said. “I’m too lazy to put on socks and shoes, and flip-flops are so easy and hassle-free.”

Sutaria said she never wears flip-flops when snow covers the sidewalks.

“They go well with scarves and gloves,” she said. “Everything on campus is pretty compact and close together, so it’s not too cold.”

No scientific study has quantified the growth of flip-flops worn in the winter. But the sandal industry has seen a sales boom in recent years as familiar shoe and clothing companies also enter the niche market.

“It’s fashion,” said Foot Locker spokesman Peter D. Brown. “It’s just what’s in right now.”

Foot Locker’s flip-flop sales have spiked in the past year, Brown said, although he declined to give specific numbers because of industry competition.

He added that no one brand has dominated. “It’s more of a look that’s just gotten to be very popular,” he said.

Rainbow Sandals, which produces 500,000 pairs of flip-flops a year, has doubled its sales each year for the past five years, said manager Jasmine J. Nelson.

Flip-flop sales heat up in March, peak during the early summer, and taper off by September, Nelson said, adding that Rainbow sells only 20 percent of its sandals between September and March.

The wintry popularity of tropical footwear begs the question: When, exactly, is it too cold for flip-flops?

For Brittin Romero, a fourth-year in the College, flip-flops stay in the back of her closet from after early October until late spring.

Except when she’s in a pinch. On Monday morning Romero drove friends to the airport, slipping on flip-flops for the car ride. Outside, the temperature was dancing around freezing point.

“I don’t do this normally,” Romero said. “I don’t want to be grouped with those crazy people who wear them all through the winter. I make fun of them.”

Diehard flip-flop wearers who want to keep their toes off the amputation table might be interested in Flip Flop Socks. A kitschy name for the traditional Japanese tabi sock, the sock has an indentation separating the big toe from the others—and making room for the thong strap.

Flipflopsocks.com, which has been in business for three years, does the bulk of its sales during the fall and winter and markets to the “hundreds of thousands” of people who wear regular socks scrunched by flip-flops, said company owner Michele Baer.

“The people who are wearing flip-flops don’t want to put shoes on,” Baer said. “People prefer to wear flip-flops all the time now. They hate to put on shoes.”