Freezing rain air at the surface within the region of high pressure. The warm air from the Gulf of Mexico is often the fuel for freezing precipitation. Freezing rain develops when falling snow encounters a layer of warm air aloft, typically around the 800 mbar (800 hPa) level, causing the snow to melt and become rain. As the rain continues to fall, it passes through a layer of subfreezing air just above the surface and cools to a temperature below freezing (). If this layer of subfreezing air is sufficiently deep, the raindrops may have time to freeze into ice pellets (sleet)
Reindeer hunting in Greenland there can be cornices, crevasses, and avalanches, although snow can make it easier to spot and track reindeer. The weather during the beginning of the autumn hunting season is often pleasant, relatively warm, and mild, but it can change very quickly. Hunters may encounter fog, rain, wind, and winter conditions. Occasionally the situation can quickly approach a worst-case scenario with events such as katabatic winds, storms, snow, hail, sleet, freezing rain, blizzards, and polar cyclones, even in the late summer. Lack of preparation can have fatal consequences. Using a compass in Greenland involves accounting for a very extreme magnetic declination.