Early snow topped the higher peaks of the Rocky Mountains of Utah, Wyoming, Montana and Colorado in the last days of summer 2019, with first snowfall recorded on September 11. This “fall-like” snowfall was followed by a wider, heavier, frigid winter blast from September 27-30 that dropped heavy, wet snow across the region, setting several records for cold temperatures as well as for September snow accumulation. According to The Weather Channel, over a dozen locations in northern Montana picked up over a foot of snow, with the highest total recorded at 48 in (4 feet/ 1.2 meters) on Browning, Montana. Great Falls, Montana recorded the two heaviest September snowfall days on record on September 28 (9.7 in/24.6 cm) and September 29 (9.6 in/24.4 cm).
The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of the snow-capped Grand Tetons and Yellowstone National Park on October 6, about one week after the major winter storm. The image encompasses parts of Idaho (west), Montana (north) and Wyoming (east). The blue color of Yellowstone Lake, the largest high elevation lake (above 7,000 feet/2,134 mi) indicates that temperatures have not yet been cold long enough to cause icing, despite the surrounding snow. Yellowstone Lake typically freezes over in December.