The piles of snow left behind after plowing often melt very slowly, even if temperatures rise. This is due to the fact that snow is quite reflective and does not absorb much energy from sunlight, as well as to its low thermal conduction. Removing this snow can cost cities a large amount of money.

Jonathan B. Boreyko, Virginia Tech, Blacksburg, USA, and colleagues have developed a cost-effective, and energy-saving method for snow removal, inspired by simple technologies used in water evaporation. The team prepared 1.3 mm-thick aluminum sheets, which were painted black either with silicone-based paint or enamel paint. The coated sheets were placed on snow kept at temperatures of about 3.5 °C and irradiated with simulated sunlight. The team then measured the melting rate of snow by weighing the meltwater. Uncoated aluminum sheets and bare snow were used as controls.

The researchers found that the black, thermally absorptive sheets increase the snow’s rate of melting by 250–300 % compared with bare snow. The enamel paint slightly outperformed the silicone-based paint. The method needs no external energy input or antifreeze chemicals. According to the team, this simple approach could reduce snow-removal costs and might be particularly useful for quickly removing snow from parking lots or driveways.

• Thermally Absorptive Blankets for Highly Efficient Snowbank Melting,
  Owen L. Hansen, Andrew B. Sheen, Kristen M. Swedberg, Karl W. Vitale, Sarah M. Wray, Matthew D. Fox, Jonathan B. Boreyko,
  Langmuir 2018.
  https://doi.org/10.1021/acs.langmuir.7b03182