The artificial Abraham Lake in the foothills of the Canadian Rockies has become know, especially among photogs, for a rare phenomenon where bubbles get frozen right underneath its surface. 

Photographer Fikret Onal says:

"The plants on the lake bed release methane gas and methane gets frozen once coming close enough to much colder lake surface and they keep stacking up below once the weather gets colder and colder during [the] winter season."

"Even though I've walked on a frozen lake before, Abraham Lake made me feel completely uneasy since the lake was not covered with snow." "Even though the icy surface was around 8-9 inches thick, it still scared the hell out of me, not only because of the fact that I could see all the cracks...and the darkness of the lake bottom through the glassy surface, but also [because of] the deep boomy, cracking sounds coming from underneath the lake's surface."