Last week, the National Weather Service in Burlington made it official: Lake Champlain has fully frozen over for the first time since February 2015. However with Thursday temperatures forecast to reach the 50s, the full freeze might not last much longer.

"A frozen Lake Champlain is really a wonderful, beautiful thing," said Matthew Vaughan, an environmental analyst with the Lake Champlain Basin Program. "It's something that I hope for every year."

But this year marks just the third time that Lake Champlain has completely frozen over since 2010.

Vaughan said the lake used to freeze over frequently, but climate change and greenhouse gas emissions have made freeze-ups much more rare. He said that trend is likely to continue.

"We're seeing less frequent ice cover on our lakes in this region. And we're also seeing a definite trend of thawing happening earlier in the season — in the springtime for our smaller lakes in the region," Vaughan said. "So unfortunately I think this will be a more rare event in the future, although I hope to see it freeze up next year as well."

Vaughan broke down the science at work when the lake freezes:

"Water has a really unique property in that when it reaches its freezing point, it actually expands into something called a crystal lattice. And this crystal lattice causes ice to float over more dense liquid water — and this is why ice cubes float on top of your drink rather than sink to the bottom," Vaughan explained.

"So there's always that warmer water down below. So when there's a light breeze over the lake, it can pull energy away from the lake's surface, but if there's a stronger wind it will mix water with that warmer water down below and delay freezing. So when we have cold temperatures and a light breeze, it can let that ice set up."

Vaughan said ice thickness and stability can quickly change, so residents should be extremely cautious on the lake. "Remember that no ice is safe ice," he warned.

And how does the freeze impact the wildlife that calls the lake their home? According to Vaughan, they're able to deal with it.

"Our fish and wildlife are well adapted for cold winters and Lake Champlain freezover, and they do quite well under the ice," Vaughan said. "Fish metabolism actually slows down quite a bit in cold temperatures and they do just fine."