A snow flurry is a common term in winter weather forecasts, used to describe an extremely light and short-lived burst of snow. This phenomenon is characterized by snow falling intermittently, often lasting only a few minutes at a time. Flurries generally produce minimal to no measurable accumulation on the ground, setting them apart from more disruptive snow events. Understanding this terminology helps in accurately interpreting winter forecasts.
Characteristics of Snow Flurries
Flurries are categorized primarily by their low intensity and short duration. The snowfall is typically light and intermittent, meaning the flakes fall sporadically rather than in a continuous stream. This results in a minimal reduction in visibility, distinguishing them from heavier snow events.
The most defining feature of a snow flurry is its lack of accumulation. While a flurry might leave a trace amount or a light dusting on surfaces, it is generally defined by the United States National Weather Service as producing no measurable precipitation. This minimal impact means flurries rarely pose significant travel risks. Flurries are also highly localized, often appearing and disappearing quickly over a small geographic area.
How Flurries Differ from Other Snow Events
The distinction between a snow flurry and a snow shower is a matter of intensity and accumulation. A snow shower involves light-to-moderate snowfall that can vary in intensity and is capable of producing some measurable snow accumulation. Conversely, flurries remain consistently light and are not expected to result in any accumulation beyond a dusting.
Unlike flurries, snow showers often originate from convective, or cumuliform, clouds, indicating a greater degree of atmospheric energy. A widespread, continuous snow event, often referred to as a snowfall or snowstorm, is fundamentally different due to its duration and spatial extent. These events are characterized by snow falling steadily over several hours, covering a much larger area, and resulting in significant, measurable accumulation.
The Atmospheric Conditions That Create Flurries
The formation of flurries requires a specific set of atmospheric ingredients, namely cold temperatures and a degree of atmospheric instability. Snow forms when the air temperature from the cloud base to the ground remains at or below freezing, allowing ice crystals to fall without melting. The process begins as water vapor freezes onto tiny particles in the cold clouds, creating ice crystals that grow into snowflakes.
Flurries are often associated with pockets of instability in the lower atmosphere, which causes air to rise and moisture to condense, but with limited intensity. This convection is not strong enough to produce the continuous, heavy precipitation of a major storm system. A common example is the “lake-effect flurry,” where cold, dry air moves across a relatively warmer body of water, picking up moisture and heat before depositing it as localized, light snowfall downwind. The turbulence and wind associated with these unstable conditions help to scatter the light snow, contributing to their brief and intermittent nature.