Clear skies over the snow-covered European Alps can be seen in this image captured by the Suomi NPP satellite's VIIRS instrument on January 29, 2018. A high pressure system kept the Alps cloud-free, while clouds surround the mountain range on both sides. To the north, low stratus clouds associated with a cold front appear over southern Germany, while dense fog in Italy's Po River Valley can be seen in the bright white areas to the south.
Most of Europe, including the Alps, has seen well above-normal temperatures this winter. Persistent westerly winds from the Atlantic have delivered relatively mild air and frequent moisture-laden storm systems across the continent. Although higher elevations in the Alps were buried under several feet of snow in recent weeks, many valley locations have seen less snow than usual this winter. In Switzerland, this January was the warmest in more than 150 years of national climate records, while neighboring Austria had its third-warmest January since records began in 1767, according to each country's national meteorological service. Several cities in Austria set new records for the greatest number of frost-free days ever observed during the month of January.
Although true-color images like this may appear to be photographs of Earth, they aren't. They are created by combining data from the three color channels on the VIIRS instrument sensitive to the red, green and blue (or RGB) wavelengths of light into one composite image. In addition, data from several other channels are often also included to cancel out or correct atmospheric interference that may blur parts of the image.