WeatherWhys: Winter Carnival is this weekend, but how are these amazing sculptures made?

·3 min read

The wait continues for the Boise area’s next major snowfall event, but that doesn’t mean Southern Idaho residents have to go another week without living their Winter Wonderland dreams.

Just 106 miles north of Boise sits McCall, home of the McCall Winter Carnival. The carnival, which has been held in the small town of just over 3,300 since the 1960s, is most famous for its snow sculpture competition that sees local businesses and artists create intricate sculptures using just snow.

This year’s carnival starts Friday and runs through next Sunday, Feb. 6.

While a series of storms sweeping through North and Central Idaho will help clear inversion conditions in the Treasure Valley, this week’s WeatherWhys has Idaho News 6 chief meteorologist Scott Dorval explain how snow sculptures are made and the conditions in and around the McCall area.

The McCall Winter Carnival

A giant wizard. Polar bears, whales and walruses. A giant steam engine. Two knights jousting on horseback.

You name it, and there’s been a snow carving of it at the Winter Carnival at some point.

The 2021 McCall Winter Carnival will take place from Friday, Jan. 28 to Sunday, Feb. 6
The 2021 McCall Winter Carnival will take place from Friday, Jan. 28 to Sunday, Feb. 6

But how are these sculptures made, and what keeps them together?

Imagine taking two blocks of ice: One block is crushed down into pieces, and the other is left standing in one piece. The crushed-up block will melt a lot faster as outside heat touches more surfaces of the ice, while the more compact, larger block of ice melts more slowly.

That’s how the ice sculptures work: Heavily compacted snow, often built with layers of water that freeze into ice, will melt a lot more slowly even if temperatures rise above the freezing point.

“When you compact snow and you raise it, now it takes more energy to permeate, to get inside there, to really soften it up,” Dorval said. “So if you’re going to build a bridge or an arch, you wouldn’t make it too thin because you want to get more snow that’s inside, so you have more strength.”

McCall Winter Carnival
McCall Winter Carnival

The weather conditions look set for a perfect festival week with blue skies until Sunday afternoon.

The McCall area has about 3 feet of compact snow on the ground, helping keep the magic of winter alive. Dorval expects a weak system to pass through the area Sunday afternoon that will drop a small amount of snow and warns travelers of slick roads if heading home on Sunday night.

For most of the weekend, temperatures will drop as low as 6 degrees in the morning. They’ll rise to the 30s during the day but stay cold enough to prevent the sculptures from melting.

Blue skies in the Treasure Valley

After two weeks of inversion conditions, the sun has been a rare sighting.

Dorval is tracking multiple storm systems set to pass through Idaho in the next week, but most of them will hit North and Central Idaho. The Treasure Valley can still expect a couple inches of snow, and the snow will finally clear out inversion conditions.

The Treasure Valley could see snow flurries on Monday, Thursday and Friday which will clear out inversion conditions.
The Treasure Valley could see snow flurries on Monday, Thursday and Friday which will clear out inversion conditions.

“The storms are coming close enough. … This is going to bring cooler air in aloft,” Dorval said. “So the upper levels of the atmosphere are going to cool off, and that’s going to take the (warm air) cap off. And then as soon as we stir the breeze up, then we can clear out clouds in the valley.”

The Boise area could see some snow showers Sunday night as well as some flurries early next Thursday and Friday, but the area should only pick up a couple inches cumulatively. Otherwise, expect to finally see blue skies again for much of next week as the layer of clouds over Southwest Idaho clears out.

With a fourth system coming through the second week of February, the Treasure Valley could see 4-6 inches of cumulative snow over the next two weeks.

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