On ice

I write these sentences on the eve of yet another snow storm in New England. For the coming two days, meteorologists have prospected that up to 24 inches of powdery snow might fall onto the North-Eastern coast of the United States and Canada [1]. The imminent blizzard is the second one of this season, with a third storm in sight. While snow has specific uses and cultural overtones, it is mostly seen as an impediment to road traffic. Snow accumulation is but a planning problem solved by snowplows and sprays of rock salt.

As writing and editing processes “naturally” go, most of the white crystals exposed to wind will have hardened through cycles of melting and freezing once this article is published. What remains are sheets of ice, thin layers of transparent solid, generally only registered as a hindrance when we almost slip on a spot of poorly salted sidewalk. Ice suggests that split second of instability, the shock of almost losing connection to the ground. Or dare say, we slip.

What makes ice slippery even well below its zero-degree Celsius melting point has been of scientific interest since initial experiments in the physics of regelation in the 1850s [2]. By applying pressure on ice through a looped rope pulled by a heavy weight, scientist Michael Faraday succeeded in letting the rope travel through ice, splitting it in two and freezing the sides together again. In his resulting paper published in 1859, he argued that a liquid layer coating the ice must be the reason for the observed phenomenon. Although frozen in place for almost a century by the reasoning of Faraday’s opponents, physicist C. Gurney (whose first name is presently unknown) recovered the findings [3]. In 1949 he confirmed the existence of an unstable, disordered film at the surface of solid ice, prompting the formation of a pre-melted phase. This, he reckoned, made ice slippery. A slippery disorder. To this day, the scientific community is studying the thermodynamic properties of the quasi-liquid layer of water molecules, as the origin of its disorder remains rather vague. What is certain is that the disordered film can become up to 45 nanometers thick [4]. Over these 160 years, the exploration of the slippery properties of ice has provided the basis for the study of ice skating and road slips. It has also helped explain the cause of glacial movements.

Screenshot taken from earth.nullschool.net; 2021-02-01 12:00 Local; Wind + Temperature @ Surface

Picture by author

It is 4 PM the coming day and snow has begun to fall.

Meteorological sciences have determined that weather regulates on a planetary scale. Changes in one region of the world lead to effects in distant others through wind circulations, precipitation patterns and oceanic currents. Disorder leads to all kinds of consequences. Scientists argue in a New York Times article that what New York, Montreal, Chicago, and all that lies between are experiencing might be the result of the warming of the Arctic [5]. The melting of ice at the North pole is thought to weaken the westerly jet stream that exists kilometers above the surface of the Earth. The circular wind entraps what is called the Polar vortex, a hub of icy weather at the upper stratospheric level. Disturbances and breaches of this circle send storms like the one I am currently experiencing southwards of the Arctic. But the melting of ice has much more local consequences. It is directly linked with the destruction of habitats and the rampant food insecurity of communities living in the North. Here in Boston though, the storm turns out to be calmer than expected.

Although slippery, ice stands as a slowing of material, the crystallization and freezing in time (and space) of water molecules. A wintering of sorts. This property makes ice an essential element for logistics. It is used to preserve foods on continental shipments, “put on ice”, but not quite frozen. More recently, new containers were developed to enclose doses of the SARS-Covid vaccine, entrapping the cocktails of mRNA at -60 to -80 degree Celsius and prolonging their span of transport.

But freezing in time is not pausing. Ice is not static, but rather moving slowly.

What can be observed on a microscopic scale on the surface of ice bares resemblance to the larger processes revolving around ice melting and the movement of glaciers. Over the Arctic, the unstable layer of ice swells for kilometers into the atmosphere. No matter the scale, ice is two things at once, never quite certain. It is freezing and melting, moving and slowing down, slippery and crystallized.

Sources:

[1] Schwartz, John. "Forecast: Wild Weather In A Warming World". The New York Times, 2021. https://www.nytimes.com/2021/01/30/climate/polar-vortex-weather-climate-change.html?smtyp=cur&smid=tw-nytimes. 

[2] Rosenberg, Robert. "Why Is Ice Slippery?". Physics Today 58, no. 12 (2005): 50-54. doi:10.1063/1.2169444.

[3] Gurney, C. "Surface Forces In Liquids And Solids". Proceedings Of The Physical Society. Section A 62, no. 10 (1949): 639-648. doi:10.1088/0370-1298/62/10/305.

[4] Max Planck Society. “Scientists Characterize the Phase Transitions of Melting Ice Layers.” Phys.org. Phys.org, December 13, 2016. https://phys.org/news/2016-12-scientists-characterize-phase-transitions-ice.html.

[5] Schwartz, John. “Forecast: Wild Weather”.