A Winter Storm Warning in Canada means severe winter weather is expected to create hazardous conditions and potentially significant impacts. A winter storm may bring a combination of heavy snow, freezing rain, strong winds, blowing snow and other dangerous conditions.
Environment and Climate Change Canada issues Winter Storm Warnings when severe weather is happening or expected to happen. Under Canada’s colour-coded weather alert system, Winter Storm Warnings can appear as Yellow, Orange or Red alerts depending on the potential risk.
The seriousness of a winter storm depends on factors such as snowfall, ice accumulation, wind, visibility, temperature, duration, location and the expected impacts.
This guide explains what a Winter Storm Warning means in Canada, why one may be issued, how serious winter storms can become, what Yellow, Orange and Red alerts mean and what to do when a Winter Storm Warning affects your area.
What Is a Winter Storm Warning?
A Winter Storm Warning is a weather alert issued when a combination of severe winter weather hazards is expected to create dangerous conditions and potentially significant impacts.
Unlike warnings that focus primarily on one weather hazard, a Winter Storm Warning may involve several types of winter weather.
Depending on the storm, conditions may include heavy snow, freezing rain, strong winds, blowing snow or rapidly changing temperatures.
The combination of multiple hazards can make travel dangerous and cause significant disruptions to communities.
Environment and Climate Change Canada issues warnings when severe weather is happening or expected to happen. Warnings provide information about expected conditions, timing, potential impacts and actions people can take to reduce their risk.
You can learn more about Winter Storm Warnings and other weather alerts in Canada.
Why Is a Winter Storm Warning Issued?
A Winter Storm Warning is issued to alert people when a combination of severe winter weather conditions is expected to create dangerous conditions or significant disruption.
The warning gives people time to monitor changing conditions, reconsider travel plans and prepare for possible transportation disruptions, power outages and other impacts.
Several weather hazards can influence the seriousness of a winter storm.
Heavy Snowfall
Winter storms can produce significant snowfall.
Heavy snow may cover roads, reduce visibility and make walking and driving difficult.
Snow may also accumulate faster than road maintenance crews can clear it.
Freezing Rain
Some winter storms produce freezing rain.
Rain freezes when it comes into contact with cold surfaces, creating ice on roads, sidewalks, trees and power lines.
Ice accumulation can make travel extremely dangerous and contribute to falling branches and power outages.
Strong Winds
Winter storms may produce strong winds.
High winds can damage trees and utility infrastructure while making travel more difficult.
Wind can also lift falling or loose snow into the air.
Blowing Snow
Blowing snow can significantly reduce visibility.
Snow may be lifted from the ground and carried across roads and open areas.
This can create dangerous driving conditions and cause previously cleared roads to become covered again.
Rapidly Changing Conditions
Winter storms can cause weather and road conditions to change quickly.
Rain may change to freezing rain or snow, temperatures may fall rapidly and visibility may deteriorate as winds increase.
Duration
The length of a winter storm can significantly influence its impacts.
Long-lasting storms may produce greater snow or ice accumulation and cause extended transportation and utility disruptions.
Environment and Climate Change Canada provides additional information about winter storms and other severe winter weather hazards that can affect Canadians.
How Serious Is a Winter Storm Warning?
A Winter Storm Warning should be taken seriously because multiple winter weather hazards may occur during the same event.
Possible impacts may include:
- Heavy snowfall
- Freezing rain
- Ice accumulation
- Strong winds
- Blowing snow
- Reduced visibility
- Snow-covered roads
- Ice-covered roads
- Dangerous driving conditions
- Traffic collisions
- Vehicles becoming stranded
- Road closures
- Flight delays and cancellations
- Public transportation disruptions
- Falling trees and branches
- Power outages
- Property damage
- School and business closures
- Disruptions to essential services
- Risks to health and safety
The seriousness of a winter storm depends on the combination, severity and duration of the hazards involved.
Environment and Climate Change Canada uses Weather Impact Guides to assess how hazardous weather may affect daily life, travel, utilities and services, land and structures, human health and community recovery.
Winter Storm Warning Colours in Canada
Winter Storm Warnings in Canada can appear as Yellow, Orange or Red alerts.
The colours move from Yellow to Orange to Red as the potential risk increases.
The colour assigned to a Winter Storm Warning is not determined solely by snowfall amounts, ice accumulation or wind speeds.
Environment and Climate Change Canada considers both the expected impacts of the event and confidence in the forecast when selecting an alert colour.
Yellow Warning – Winter Storm
A Yellow Warning – Winter Storm indicates hazardous weather that may cause damage, disruption or health impacts.
Environment and Climate Change Canada describes the expected impacts of Yellow alerts as generally moderate, localized and/or short-term.
During a Yellow Warning – Winter Storm, possible impacts may include snow-covered or icy roads, reduced visibility, difficult travel and localized transportation or utility disruptions.
Although Yellow represents the lowest of Canada’s three alert colours, winter storms can still create dangerous conditions.
People in affected areas should monitor current weather information, check road conditions and prepare for possible disruptions.
Orange Warning – Winter Storm
An Orange Warning – Winter Storm indicates a greater level of potential risk than a Yellow alert.
Orange alerts indicate severe weather that is likely to cause significant damage, disruption or health impacts.
The expected impacts may be major, widespread and/or last for several days.
During an Orange Warning – Winter Storm, possible impacts may include dangerous or impossible travel, significant snow and ice accumulation, widespread transportation disruptions and power outages.
Communities may experience school and business closures, road closures and interruptions to essential services.
People in affected areas should closely monitor official information, reconsider unnecessary travel and prepare for significant disruptions.
Red Warning – Winter Storm
A Red Warning – Winter Storm represents the highest level of potential risk within Canada’s colour-coded weather alert system.
Red alerts indicate very dangerous and possibly life-threatening weather that is expected to cause extreme damage and disruption.
The expected impacts may be extensive, widespread and prolonged.
During a Red Warning – Winter Storm, exceptionally severe conditions may make travel impossible, isolate communities and cause extensive damage to infrastructure.
Widespread and prolonged power outages, major transportation shutdowns and significant disruptions to essential services may occur.
Red alerts are rare and communicate the most serious potential weather risk within Canada’s alert system.
People in affected areas should follow official information and instructions from local authorities and emergency officials.
Environment and Climate Change Canada provides additional information about Yellow, Orange and Red weather alerts and how the colours communicate increasing levels of potential risk.
Yellow vs Orange vs Red Winter Storm Warnings
The main difference between Yellow, Orange and Red Winter Storm Warnings is the level of potential risk communicated by the alert colour.
A Yellow warning indicates hazardous weather that may cause moderate, localized or short-term impacts.
An Orange warning indicates severe weather that is likely to cause significant impacts that may be major, widespread or last for several days.
A Red warning indicates very dangerous and potentially life-threatening weather that is expected to cause extreme impacts that may be extensive, widespread and prolonged.
| Alert colour | General meaning | Potential winter storm impacts |
|---|---|---|
| Yellow | Moderate, localized or short-term impacts | Difficult travel and localized transportation or utility disruptions |
| Orange | Major, widespread or prolonged impacts | Dangerous travel, closures, outages and significant disruption |
| Red | Extreme, widespread and prolonged impacts | Impossible travel, extensive infrastructure impacts and severe disruption |
The warning colour is selected using both expected impacts and forecast confidence.
Environment and Climate Change Canada’s Alert Colour Matrix explains how forecasters combine expected impacts and forecast confidence when selecting Yellow, Orange or Red.
Can the Colour of a Winter Storm Warning Change?
The colour assigned to a Winter Storm Warning reflects the potential risk associated with the expected event.
Environment and Climate Change Canada considers expected weather impacts and forecast confidence when selecting alert colours.
Forecast conditions, expected impacts and forecast confidence may change as a winter storm develops and new information becomes available.
For this reason, people should continue monitoring the latest Winter Storm Warning rather than relying only on an earlier alert.
Always read the complete warning because it may include updated information about expected snow, freezing rain, wind, visibility, timing, affected locations and recommended actions.
Winter Storm Warning vs Snowfall Warning
A Winter Storm Warning and Snowfall Warning can both involve significant snow, but they describe different types of weather events.
A Snowfall Warning focuses primarily on significant snowfall that is expected to create hazardous conditions.
A Winter Storm Warning may involve a combination of severe winter weather hazards.
Depending on the event, these hazards may include snow, freezing rain, strong winds and blowing snow.
The appropriate warning depends on the weather conditions and expected impacts.
Winter Storm Warning vs Blizzard Warning
A Winter Storm Warning and Blizzard Warning both communicate potentially severe winter weather.
A Blizzard Warning focuses on strong winds combined with falling or blowing snow that create widespread, severely reduced visibility.
A Winter Storm Warning may involve several winter weather hazards occurring during the same event.
A winter storm can produce significant snow, freezing rain and strong winds without meeting the conditions associated with a Blizzard Warning.
Winter Storm Warning vs Freezing Rain Warning
A Winter Storm Warning and Freezing Rain Warning may both involve ice accumulation.
A Freezing Rain Warning focuses specifically on freezing rain and the hazardous conditions it may create.
A Winter Storm Warning may involve freezing rain as one of several severe winter weather hazards.
For example, a storm may produce snow followed by freezing rain and strong winds.
Winter Storm Warning vs Snow Squall Warning
A Winter Storm Warning and Snow Squall Warning both involve hazardous winter weather, but the events are different.
A Snow Squall Warning focuses on intense, localized bands of snow that can cause sudden reductions in visibility and rapidly changing road conditions.
A Winter Storm Warning generally involves a larger weather system and may produce several different winter hazards.
Winter Storm Warning vs Winter Storm Watch
A Winter Storm Warning and Winter Storm Watch communicate different levels of certainty about severe winter weather.
A Winter Storm Watch means conditions are favourable for a severe winter storm to develop.
A Winter Storm Warning means severe winter weather is happening or expected to happen.
A Watch gives people advance notice to monitor conditions and prepare for the possibility of severe weather.
A Warning indicates a more immediate threat and means people should take appropriate precautions.
What Can Happen During a Winter Storm Warning?
The impacts of a Winter Storm Warning depend on the combination, severity and duration of the weather hazards.
Dangerous Travel Conditions
Snow, freezing rain and blowing snow can make roads difficult or impossible to use.
Drivers may encounter slippery roads, reduced visibility and rapidly changing conditions.
Road Closures
Authorities may close roads and highways when conditions become too dangerous for travel.
Closures may continue after the storm ends while roads are cleared and hazards are removed.
Transportation Disruptions
Flights, trains, buses and other transportation services may be delayed or cancelled.
Disruptions may continue while snow and ice are cleared.
Power Outages
Strong winds, ice accumulation and falling trees can damage electrical infrastructure.
Outages may continue after the storm ends while repairs are completed.
Falling Trees and Branches
Heavy snow, ice and strong winds may damage trees.
Falling branches can damage homes, vehicles, roads and power lines.
School and Business Closures
Severe winter conditions may cause schools, businesses and public facilities to close or change operating hours.
Disruptions to Essential Services
Severe winter storms may affect transportation, utilities and other services.
Emergency response may also become more difficult when roads are blocked or dangerous.
What Should You Do During a Winter Storm Warning?
The appropriate response to a Winter Storm Warning depends on the alert colour, local conditions, expected impacts and instructions from authorities.
Monitor Current Conditions
Check current weather alerts, forecasts and radar regularly.
Winter storms can change as they develop.
Environment and Climate Change Canada provides official weather radar and satellite services that can help people monitor approaching precipitation.
Reconsider Unnecessary Travel
Consider delaying unnecessary trips when dangerous winter weather is expected.
Conditions may deteriorate rapidly after a trip begins.
Check Road Conditions
Review current highway conditions, closures and transportation information before travelling.
Road conditions may vary significantly between communities.
Prepare for Power Outages
Snow, ice and strong winds may damage utility infrastructure.
Monitor information from your utility provider and prepare for possible disruptions.
Stay Away From Downed Power Lines
Never approach or touch a downed power line.
Keep a safe distance and report damaged electrical infrastructure to the appropriate authorities or utility provider.
Follow Official Information
Continue monitoring Environment and Climate Change Canada and follow road closures, travel recommendations and instructions from local authorities.
The Government of Canada provides additional guidance on how to prepare for winter storms.
Can You Drive During a Winter Storm Warning?
Driving during a Winter Storm Warning may be difficult, dangerous or impossible depending on the severity of the event.
Snow can cover roads and reduce visibility.
Freezing rain can create ice-covered surfaces, while strong winds and blowing snow may make it difficult to see and control a vehicle.
Before travelling, check current weather and road information.
Consider delaying unnecessary trips when severe winter weather is expected.
Follow road closures and travel recommendations issued by authorities.
How Long Does a Winter Storm Warning Last?
There is no standard duration for a Winter Storm Warning.
The length of the warning depends on the weather system, hazards involved, expected impacts and forecast confidence.
Some winter storms may affect an area for several hours.
Large or slow-moving weather systems may create dangerous conditions and significant disruptions for several days.
Impacts may continue after the storm ends.
Road closures, power outages and transportation delays may remain while communities recover and infrastructure is repaired.
What Causes a Winter Storm?
Winter storms develop when atmospheric conditions allow cold air, moisture and weather systems to interact.
The specific conditions determine the type of precipitation and hazards produced.
A winter storm may bring snow when temperatures remain cold enough throughout the atmosphere.
Freezing rain can develop when snow melts while falling through a layer of warmer air before freezing on contact with cold surfaces.
Strong differences in atmospheric pressure may also produce powerful winds.
Because temperature and atmospheric conditions can vary throughout a storm, the type of precipitation may change as the weather system moves through an area.
When Is Winter Storm Season in Canada?
Winter storms can occur at different times depending on the region.
In many parts of Canada, winter storm activity is most common from late fall through early spring.
Northern and higher-elevation regions may experience winter weather outside this period.
The timing and severity of winter storms vary significantly across the country because of Canada’s size and diverse climate.
How Can You Check Current Winter Storm Warnings?
Current Winter Storm Warnings and other weather alerts can be checked through Environment and Climate Change Canada’s official weather services.
The Weather Information map allows users to view current alert areas and read the complete alert text for affected locations.
You can use the official Weather Information map to check current forecasts and alerts across Canada.
The WeatherCAN application also provides official forecasts, alerts and customizable notifications.
Frequently Asked Questions About Winter Storm Warnings
A Winter Storm Warning means severe winter weather is happening or expected and may involve a combination of snow, freezing rain, strong winds, blowing snow or other hazardous conditions.
A Winter Storm Warning can indicate dangerous conditions and significant disruption, including hazardous travel, road closures, power outages and transportation cancellations.
A Yellow Warning – Winter Storm indicates hazardous weather that may cause moderate, localized or short-term impacts.
An Orange Warning – Winter Storm indicates severe weather that is likely to cause significant impacts that may be major, widespread or prolonged.
A Red Warning – Winter Storm represents the highest alert colour and indicates very dangerous and potentially life-threatening weather expected to cause extreme impacts.
A Snowfall Warning focuses primarily on significant snowfall. A Winter Storm Warning may involve a combination of snow, freezing rain, strong winds and blowing snow.
A Blizzard Warning focuses on strong winds and falling or blowing snow that create widespread, severely reduced visibility. A Winter Storm Warning may involve several winter hazards occurring together.
A Winter Storm Watch means conditions are favourable for severe winter weather to develop. A Warning may be issued when severe winter weather is happening or expected.
Sources
- https://www.canada.ca/en/services/environment/weather/severeweather/weather-alerts.html
- https://www.canada.ca/en/environment-climate-change/services/seasonal-weather-hazards/severe-winter.html
- https://www.canada.ca/en/services/environment/weather/severeweather/weather-alerts/weather-impact-guides.html
- https://www.canada.ca/en/services/environment/weather/severeweather/weather-alerts/colour-coded-alerts.html
- https://www.canada.ca/en/services/environment/weather/severeweather/weather-alerts/choose-alert-colours.html
- https://www.canada.ca/en/services/environment/weather/radar-satellites.html
- https://www.canada.ca/en/services/policing/emergencies/preparedness/get-prepared/hazards-emergencies/winter-storms/how-prepare.html
- https://www.canada.ca/en/environment-climate-change/services/weather-general-tools-resources/weather-webmapping.html
- https://www.canada.ca/en/environment-climate-change/services/weather-general-tools-resources/weathercan.html