What you need to know about snow storms

Introduction: Why snow storms matter

Snow storms are a major winter hazard where freezing temperatures coincide with precipitation such as snow, mixed snow and rain, or freezing rain. Their relevance extends from everyday disruptions — school closures and hazardous travel — to serious infrastructure and safety impacts, including power outages, damaged lines and avalanche risk in mountain areas. Understanding how snow storms form and the risks they pose helps communities prepare and respond effectively.

Main body: Definitions, types and key facts

What is a winter storm?

A winter storm is a weather event in which wind coincides with precipitation that only occurs at freezing temperatures. Precipitation types include snow, sleet, mixed snow and rain, and freezing rain. Winter storms range from localized events lasting around 24 hours to large systems covering large geographic areas for several days.

Visibility, wind and snow intensity

Falling snow reduces visibility, and strong winds commonly associated with winter storms further worsen conditions. Conditions of concern include winds or gusts of 35 mph (or more) combined with snow or blowing snow that can reduce visibility to less than a quarter mile for three hours or more. Intense, brief bursts of heavy snow — known as squalls — and blowing snow that lifts snow already on the ground can rapidly degrade travel safety.

Ice storms and comparative impacts

Ice storms can have outsized impacts compared with equivalent liquid or snow amounts. For example, while a 10 cm (3.9 in) snowfall may be manageable in many northern regions, a relatively small 10 mm (0.39 in) accumulation of freezing rain can paralyse a region by making driving hazardous, damaging telephone and power lines, and ruining crops. Historical events, such as a December Ice Storm that produced extensive ice damage across a large portion of the southern United States from December 14–16, illustrate these risks.

Mountain hazards and avalanches

In mountainous areas, heavy snow can trigger avalanches. More than 80 percent of midwinter avalanches are triggered by rapid accumulation of snow, and 90 percent of those avalanches occur within 24 hours of snowfall, making rapid-onset storms particularly dangerous for backcountry and mountain travel.

Conclusion: Significance and preparedness

Snow storms can disrupt daily life, damage infrastructure and pose acute safety risks. Readers should expect possible heavy snow or ice, strong winds and freezing temperatures during winter storms, and consider preparedness measures such as limiting travel, securing power-dependent needs and heeding local forecasts and warnings. Awareness of the specific hazards — reduced visibility, icing and rapid snow accumulation in mountains — helps communities and individuals reduce risk and respond promptly when storms occur.