Winter gives a lot of interesting optical phenomena. It’s on professional language called purple radiance. It’s good studied and fairly widespread, although rarely intense. 
A photo from open sources
Purple sunset © littleny | Shutterstock.com Once Upon a Time saturated pink sunset has alarmed Moscow in January 2010. Then meteorologists had to reassure residents of the capital, explaining that this has nothing to do with toxic industrial emissions, but is exclusively a game of sunlight, scattered by the atmosphere and repeatedly reflected in snow crystals.
A photo Open Source Purple Dawn © Dean Pennala | Shutterstock.com Purple Dawn is a rarer occurrence. It occurs when the sun is still below the horizon below 4 degrees, the air is frosty, filled with ice crystals, and there is snow all around. The duration of the phenomenon is 20-30 minutes. The intensity of the purple radiance increases with increasing transparency of the air and increasing the height of the observation site. In that the day you could see the classic purple sunset, bright expressed due to low temperature and sufficient humidity. In addition, this effect has spread widely due to multiple reflection of light from highly layered clouds, falling snow and snow cover.
Snow
