A storm of blowing snow with high winds and low temperatures. Blizzards are a notable climatic feature of the northern and central parts of the USA in winter, and are related to depression tracks. In the USA, a blizzard is defined by the National Oceanic and Atmospheric Administration (NOAA) as a storm with winds of at least 56 km/h, temperatures below −6.7  °C, and enough falling or blowing snow to reduce visibility to less than 0.4 km. In a severe blizzard, wind speed is at least 72.5 km/h, temperatures below −12.2  °C, and visibility is close to zero.