An ice storm is a type of winter storm characterized by freezing rain, also known as a glaze event or, in some parts of the United States, as a silver thaw. The U.S. National Weather Service defines an ice storm as a storm which results in the accumulation of at least 0.25-inch (6.4 mm) of ice on exposed surfaces. From 1982 to 1994, ice storms were more common than blizzards in the U.S., averaging 16 per year. They are generally not violent storms but instead are commonly perceived as gentle rains occurring at temperatures just below freezing.
A massive ice storm struck northern New England and southeastern Canada during 7-9 January 1998. This storm was devastating to power and telephone transmission lines and had great impact on vegetation, particularly the deciduous forest at higher elevations (>500 m). The storm has been described as the worst of this type in a century.