In the Caucasus Mountains, cold, dry air from Asia intersects with humid air from the Mediterranean, making precipitation amounts uneven across the range. You might remember the concerns prior to the 2014 Olympic Games about whether venues in Sochi and the western Caucasus would have enough snow for the sporting events.
Thanks to its proximity to the Black Sea, the western side of the range typically sees the heaviest snowfall. Humid air over the sea gets blown north and east and rises as it is forced upward by the mountains, which rise sharply just 100 kilometers (60 miles) from the shore. The air cools and the moisture drops out as snow. This part of the range receives about 240 centimeters (90 inches) of precipitation per year. Those totals contrast sharply with northern and eastern parts of the range—located in a rain shadow—where less than 40 centimeters (16 inches) of precipitation falls per year.
On February 2, 2018, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired a natural-color image (above) of the snowcapped Caucasus range. Russia is visible in the top and right of the image, while Georgia, Azerbaijan, Armenia, and Turkey fill the bottom and left.
Some of this snow could last well into spring and even summer. Snow that falls above elevations of 2500 meters in the western Caucasus can last for more than 200 days. That’s almost a month longer than the snow sticks around at similar elevations on the drier eastern range.
About 1500 kilometers (900 miles) to the north, Moscow and surrounding areas of Russia were also blanketed in white this week. Over a span of 36 hours on February 3–4, 2018, as much as 55 centimeters (22 inches) of snow fell around the capital city. According to news reports, the storm delivered as much snow as Moscow would typically see in an entire month. When skies cleared again on February 6, Terra MODIS acquired this view of the snowscape.
References and Further Reading
- Hughes, K.K. and Mayes, J. (2004) Understanding Weather, (Routledge).
- RadioFreeEurope (2018, February 5) Moscow Battles 'Snowfall Of The Century'. Accessed February 7, 2018.
- Reuters (2018, February 5) Russia calls in army after 'snowfall of the century' in Moscow. Accessed February 7, 2018.
- Tielidze, L.G. (2016) Glacier change over the last century, Caucasus Mountains, Georgia, observed from old topographical maps, Landsat and ASTER satellite imagery. The Cryosphere, 10 (2016), 713-725.
NASA Earth Observatory images by Jeff Schmaltz, using MODIS data from LANCE/EOSDIS Rapid Response. Story by Kathryn Hansen.
- Terra - MODIS