Snow & Ice
Essential snow and ice terminology — from blizzards to snow squalls. Understand every winter weather term that affects school closures and road safety.
Blizzard
A severe winter storm officially defined by sustained winds over 35 mph, considerable falling or blowing snow, and visibility under a quarter-mile for at least three hours. Snow accumulation is not part of the criteria.
Blowing Snow
Snow lifted from the surface by wind, typically reducing visibility to under seven miles. Blowing snow is a primary driver of school and road closures even when no new snow is falling.
Freezing Rain
Rain that falls as liquid but freezes on contact with cold surfaces. It coats roads, trees, and power lines with a glaze of ice and is one of the most disruptive winter precipitation types.
Lake-Effect Snow
Heavy, localized snowfall produced when cold air passes over warmer lake water, picking up moisture that falls as snow downwind. Cities like Buffalo, NY can receive several feet of snow from a single lake-effect band while areas just miles away see nothing.
Sleet
Frozen pellets of ice formed when raindrops refreeze before hitting the ground. Sleet bounces on impact, unlike freezing rain, which coats surfaces.
Snow Day
A day on which schools or workplaces close due to heavy snow, ice, or dangerous wind chill. Closure decisions depend on accumulation rate, road conditions, and the timing of the storm relative to the morning commute.
2-Hour Delay
A school schedule adjustment that postpones the start of the school day by two hours, typically used when road conditions are expected to improve by mid-morning. Two-hour delays allow districts to avoid a full closure while still keeping students safe during the worst of the morning commute. Also called a 'late start' or 'delayed opening.'
Snow Squall
A brief, intense burst of heavy snow accompanied by gusty winds that drops visibility to near zero. Snow squalls are notoriously dangerous on highways and trigger emergency advisories from the National Weather Service.
Snowfall Accumulation
The total depth of snow on the ground after a storm, typically measured in inches. The rate of accumulation often matters more than the total: 4 inches in an hour is far more disruptive than 8 inches over a full day.
Snowpack
The layer of accumulated snow that builds up over a winter season, especially in mountain regions. Snowpack is critical for spring water supply and is closely monitored by water resource agencies.