Passersby and self-made snow artists alike had to tiptoe carefully and duck for cover so as not to squash a sculpture in progress or get smacked by a renegade snowball during the Snow Art Flash Mob, on Saturday in Union Square.

Orchestrated by the Somerville Arts Council’s ArtsUnion Winter Series and Artisan’s Asylum, the event drew dozens of bundled-up revelers to Union Square for an afternoon of public art, free Mexican hot chocolate, music and snowball fights. 

“Six hours ago, there were a couple of little snow blown paths right through here and everything looked kind of grungy," said Gui Cavalcanti, cofounder of Artisan’s Asylum. "Now there are forts, there are Calvin and Hobbes scenes, there are big dragons. You know, its a lot of fun,” he added .

Snow dragons, snow forts, snow goons, snow sharks, snow creatures of all sorts and even a Snow-Decahedron sprung up high and low around the Square. 

 Artist Dan Sternof Beyer explained his "Snow-Decahedron,” a twelve-sided shape made up of regular pentagons, was a model of a dodecahedron—a shape discovered by ancient Greek mathematicians and hidden from the public.

“So to put a dodecahedron back into the public is to give the public back this elite hidden knowledge of the high echelons of mathematicians, and also it's just a beautiful shape,” Sternof-Beyer said. “That they don't actually occur naturally in nature is another fascinating thing,” he added. 

Ancient Greek knowledge was also put to work to decide what would become of a giant snow mound on the eastern side of the square. Jennifer, who attended the event with her son, said the 20-foot-long dragon was the result of a democratic vote. 

“We voted. It almost was a shark, and then it was a shark dragon, and now it's a dragon,” she said.

Meanwhile, as the dragon took shape, Ann got to work with plastic buckets and shovels to build a fort, complete with a moat, to create “a safe space to avoid the dragon,” she said. 

And Claire Blechman and Tim Hannafin went to work building mini snow people, and stacking them high atop some of the already existing public art in the square. They called the sculptures, “Snow Rises.”

Jim Cote also stopped by with his sons, Ethan, 14, and Samuel, 11, for some snow sculpting after spending the morning at the Winter Farmers Market.

Once the forts were erected, the dragons hatched and the creatures awoken, like any good snow frolicking session, the scene turned into a mass snowball fight. Neighboring forts barraged one another using snowball cannons and shovels full of snow, while brave children forged ahead and crossed enemy lines to make direct hits on their opponents.

Others simply danced along to the music weaving pitches and dodges into their dances, while sipping hot chocolate and warming frosted fingers. 

Story by Katie Lannigan. Photos by Riordan Galluccio and Katie Lannigan.