“I went out on the ice, this black ice, and it looked like the starry night sky. You could see these bubble clusters everywhere. I realized — ‘aha!’ — this is where all the methane is.” (View a slide show of her at work setting “bubble traps.”)

The increasing rapidity at which these photos spread through social media has meant that a wide array of people across the globe are learning about them and finding their own — potentially precarious — ways to get up close to the bubbles.

“It’s an eerie experience because the lake is so clear that you can see down to the bottom; if there are no cracks or bubbles to use as a reference you can’t tell how thick the ice is, and it feels as though you could fall through at any moment,” wrote Ms. Ross, who is a Ph.D candidate in experimental psychology at the University of Calgary. She said she wore spikes on her shoes so as not to be swept away by wind when capturing her image of her feet.

Falling through is actually a real concern.

“January is probably the safest,” said Madeleine Ernst, who is the proprietor of the nearby Aurum Lodge, which offers tours of the lake. In mid-February the ice begins to thaw, meaning it gets more dangerous. Mr. Ernst said Thursday, that as it has now warmed to the point that she no longer could spot any bubbles.

Visitors often wonder of another danger: flammability. When methane finally reaches the air and mixes with oxygen, it can ignite with the spark of a match as you can see in this video, shot at a lake in Norway in 2014. Rune Pettersen, a YouTube experimenter, punctured the ice to release methane into the air before lighting it with a match.