Why Did a Huge Pile of Boston Snow Linger Til Mid-July?

For months, Bostonians have marveled — or else recoiled in disgust — at a giant 75-foot-high, 4-acre pile of dirty snow left over from last winter’s record snowfall, which lingered for months in an empty lot on Tide Street in the city’s Seaport district.

The snow mountain actually was a man-made curiosity, the last of 11 such “snow farms” that Boston workers created out of desperation, as the city was inundated with frozen precipitation. The city’s Public Works department’s snowplows worked overtime, clearing the equivalent of 12 trips around the Earth’s equator,and deposited an astonishing 50,000 tons of snow at the snow farm sites.

But unlike the other piles of snow, the big kahuna didn’t melt. In a city filled with historic landmarks, it became a perversely odd sightseeing spot, one that curious passers-by often used as a backdrop for snapshots.

In April, a local resident posted a video of himself skiing down the side of the snow pile, a feat which required him to dodge refuse ranging from rusted lawn chairs to parking cones. (“This post-apocalyptic, sludge-coated amalgamation of snow … was good enough for me,” he commented afterward.)

Boston Mayor Martin J. Walsh even got in on the fun by staging the Boston Snow Melt Challenge, in which residents could guess when the Tide Street mound would finally melt away.

Finally, the Boston Globe reported on Monday morning that the last of the once-giant mound of snow apparently had melted. “Based on my close proximity this morning, it’s really just a pile of trash at this point,” Elise Musumano, an employee at a nearby business, told the Globe.

But you probably have a question lingering in your mind. Why did the giant snow pile last until mid-summer? The reason is that snow and ice don’t just instantly melt when the surface air temperature rises above freezing. As the physics website Splung.com, explains, when a substance is in the solid phase, it requires additional energy to break the bonds holding its molecules in place. That necessary phase-changing energy is called latent heat.

While solar radiation provided a potential source of that energy, getting it to penetrate the snow mound was another thing entirely. As this Boston Globe article explains, the mound was filled with air pockets, which served as an effective insulator. Rain would have helped to break down that insulation by piercing the mound’s surface. But unfortunately, Boston had a spring that was relatively dry as well as being unusually cold.

From Discovery News