December is a dark month. In many places where people only experience a few hours of sunlight every day, December is a about fighting off the dark. In northern Sweden an energy company installed solar powered UV-lights at bus stops to offer a daily dose of light. The CEO of the company explained that they had seen an opportunity for installing the lights since there was no snow yet.
A snow-covered landscape is brighter than any other. This is because of the albedo effect. Albedo is a unit for the ‘reflective power of a surface’ and can be experienced by wearing a black t-shirt on a sunny day. Black surfaces absorb most radiation as heat and reflect very little (a low albedo). White surfaces, on the other hand, reflect most of the light and absorb very little radiation as heat (high albedo). Depending on how fresh the snow is, its albedo is typically between 95–80% (compared to 5–30% for other parts of landscape). The snow on the ground is often even brighter than the sky above it, especially under a blue sky.
In northern Sweden the UV-lights were quickly removed since they were actually so bright that they blinded the bus drivers working in the area. Luckily, a few days later the snow fell and finally brought some much needed light…
…In addition to the daily traffic problems and loud complaints from the general public as they desperately count down to the day it all goes away.