Precipitation types the preceding adjective "freezing", becoming known as freezing rain or freezing drizzle. Frozen forms of precipitation include snow, ice needles, sleet, hail, and graupel. Their respective intensities are classified either by rate of fall, or by visibility restriction. Precipitation falls in many forms, or phases. They can be subdivided into: The parenthesized letters are the METAR codes for each phenomenon. Precipitation occurs when local air becomes saturated with water vapor, and can no longer maintain the level of water vapor in gaseous form. This occurs when less dense moist air cools, usually when an airmass rises through the atmosphere. However,
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.