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Canadian Marine Warning Program

Environment Canada’s Meteorological Service is responsible for providing Canadians with a marine warning service that ensures the safety and security of life, shipping, and protection of the natural environment. Our Marine Warning Program is intended to provide an effective warning service for hazardous meteorological and sea state conditions. The program is active year-round, except in regions where shipping is not possible due to prevailing ice conditions.

Environment Canada’s Marine Warning Program consists of two main elements:  Watches and Warnings. Watches and Warnings are issued for a variety of potentially hazardous conditions that could occur, or are expected to occur, in the marine environment during the valid period of the marine forecast. 

Marine Watches are designed to alert mariners to the possibility that marine weather conditions may develop locally which could pose a hazard and negatively impact marine operations. Marine watches are usually issued for events where there is uncertainty about the area affected or the timing of the event. When a watch is issued, mariners in the area should be prepared to take appropriate action to ensure their safety and security. For example, mariners should review appropriate emergency plans, identify safe passage to the nearest sheltered harbour, maintain vigilance, and monitor the marine forecast for further updates or warnings.

Marine Warnings are designed to alert mariners to hazardous marine weather conditions that have already developed, or are forecast to develop, either locally or throughout the entire marine area under the warning. When a warning is issued it is time to put your emergency plan into action, such as making for safe harbour. Mariners should maintain vigilance and monitor the marine forecast for further updates or warnings.

Environment Canada's Marine Warning Program

Warnings and watches issued by
Environment Canada's Marine Warning Program
CategorySub-categoryWarningsWatches
Wind
Freezing Spray
  • n/a
Localized
Ice

Another type of message used to describe marine weather conditions of interest or concern to mariners is the Marine Weather Statement. This statement may be issued when the forecast marine weather conditions are unusual or when there is potential for the development of hazardous marine weather conditions. These statements can describe non-severe, but potentially hazardous conditions, as well as other information about a variety of conditions not covered by warnings or routine forecasts.

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Wind Warnings

Wind warnings are typically issued for more than one marine forecast area at a time. Marine wind warnings are included in the Recreational Boating Forecast, where available, and the Regular Forecast bulletins, and are conveyed using the keywords “in effect”.

There are four categories of wind warnings that are recognized by Environment Canada (Strong Wind, Gale, Storm, and Hurricane Force Wind). Wind warnings are issued with as much advance notice to mariners as possible, in an effort to provide them with the opportunity to make timely decisions about their safety and security.

Strong Wind Warnings

Strong Wind Warnings are issued when wind speeds of 20 to 33 knots, excluding gusts, are occurring or are expected to occur. These warnings are primarily issued during the recreational or summer boating season and are intended for coastal or inland waters only. Note that Strong Wind Warnings are not issued for marine areas where strong winds occur frequently (i.e. offshore marine areas, and most marine areas adjacent to Newfoundland and Labrador).

Environment Canada's Strong Wind Warning program activity

Regions, time frames and areas that are included in
Environment Canada's Strong Wind Warning Program
RegionStart Date *End Date *Areas Covered
Pacific CoastMarch 20November 11
  • Juan de Fuca Strait
  • Haro Strait
  • Howe Sound
  • Strait of Georgia
  • Johnstone Strait
  • Queen Charlotte Strait
Hudson, Mackenzie and Arctic WatersSpringFall
  • Mackenzie River
  • Great Slave Lake
  • Lake Athabasca
Manitoba LakesMay 1November 15
  • Lake Manitoba
  • Lake Winnipegosis
  • Lake Winnipeg
Great LakesMay 1October 31
  • Great Lakes (from Superior to Cornwall)
  • Lake of the Woods
  • Lake Nipigon
  • Lake Nipissing
  • Lake Simcoe
  • North Channel
St. LawrenceMay 1October 15
  • St. Lawrence River (Cornwall to Anticosti Island)
Atlantic Coast-MaritimesApril 15November 15
  • Fundy
  • Grand Mahan
  • Lurcher
  • Southwestern Shore
  • Fourchu
  • Cabot Strait
  • Northumberland Strait
  • Gult - Magdalen
  • Chaleur - Miscou
  • Anticosti
  • Bras d'Or Lakes
  • Halifax Harbour and
  • Approaches
Atlantic Coast - Newfoundland and LabradorN/AN/ANo Strong Wind Warning program due to prevailing wind conditions

Note: *Strong Wind Warning program start and end dates may vary and are dependent upon prevailing wind conditions

Gale Warnings

Gale Warnings are issued when wind speeds of 34 to 47 knots, excluding gusts, are occurring or are forecast to occur. These warnings are relevant to all marine interests and can be issued for all marine areas (coastal, inland and offshore) that have a regular or recreational marine forecast.

Storm Warnings

Storm Warnings are issued when wind speeds of 48 to 63 knots, excluding gusts, are occurring or are forecast to occur. These warnings are relevant to all marine interests and can be issued for all marine areas (coastal, inland and offshore) that have a regular or recreational marine forecast.

Hurricane Force Wind Warnings

Hurricane Force Wind Warnings are issued when winds of 64 knots or greater, excluding gusts, are occurring or are forecast to occur. These warnings are relevant to all marine interests and can be issued for all marine areas (coastal, inland and offshore) that have a regular or recreational marine forecast. Note that a Hurricane Force Wind Warning does not suggest that a hurricane is expected, only that the expected wind speeds will be comparable.

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Freezing Spray Warnings

Freezing Spray Warnings are relevant to all marine interests and can be issued for all marine areas (coastal, inland and offshore) that have a regular or recreational marine forecast. Freezing Spray Warnings are issued when moderate or severe freezing spray is occurring or is forecast to occur. Moderate or severe freezing spray implies ice build-up at rates of 0.7 cm/hr or faster.

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Localized Watches and Warnings

Localized Watches and Warnings are relatively short in duration and are typically issued for a single marine forecast area or portion of a marine area. Localized Watches and Warnings are issued in a special bulletin that indicates the status of the event, using the keywords “new” or “in effect” or “ended.”

Localized Watches and Warnings can be issued for such hazardous events as Squalls, Tornadoes, Waterspouts, High Water Levels and any other undefined event using a Special Marine notice. Localized Watches and Warnings are only issued on short notice (less than six hours in advance) and are ended soon after the prevailing conditions have passed.

Squall Watches and Warnings

Squalls usually occur when conditions, such as severe thunderstorms, are affecting a marine area. Squall Watches and Warnings are relevant to all marine interests and can be issued for all marine areas (coastal, inland and offshore) that have a regular or recreational marine forecast.

Squall Watches come into effect when there is the possibility of sudden, strong, gusty winds of 34 knots or greater over the marine area.

Squall Warnings come into effect when sudden, strong, gusty winds of 34 knots or greater are either forecast or observed over the marine area.

Tornado Watches and Warnings

Tornadoes can develop when conditions, such as severe thunderstorms, are affecting a marine area. Tornado Watches and Warnings are relevant to all marine interests and can be issued for all marine areas (coastal, inland and offshore) that have a regular or recreational marine forecast being produced for them.

Tornado Watches come into effect when severe thunderstorms have developed over a marine area, and the conditions are conducive for the development of one or more tornadoes within the marine area during the time specified in the watch.

Tornado Warnings come into effect when there is evidence of tornado formation (i.e. reliable observation, radar, etc.), or an existing tornado is moving from land to an adjacent marine area. Details about the expected development, movement and duration of the tornado will be provided in the warning message.

Waterspout Watches

Waterspouts can form during unstable conditions when cool air moves over relatively warmer water. Waterspout Watches are relevant to all marine interests and can be issued for all marine areas (coastal, inland and offshore) that have a regular or recreational marine forecast.

Waterspout Watches come into effect when conditions for the development of cold-air waterspouts are forecast over a marine area during the time specified in the watch.

High Water Level Warnings

Abnormally high water levels along coastal regions can be caused by the development of one or more of the following events in combination: tropical or non-tropical storms, strong winds, high waves, and high tides. High Water Level Warnings are relevant to all coastal marine forecast areas that have a regular or recreational marine forecast along the shores of the Great Lakes and the coasts of New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland and Labrador.

High Water Level Warnings come into effect in order to warn mariners and coastal populations, about the potential impacts of abnormally high water levels or waves on coastal or shoreline areas.

Special Marine Watches and Warnings

All other non-specified marine weather conditions that may warrant a watch or warning being issued will be covered in a Special Marine Watch or Warning.

Special Marine Watches can be issued when conditions are conducive for the development of any other weather-related phenomena that may pose a hazard to local marine operations. For example, a marine forecaster may decide to issue a Special Marine Watch when a small band of freezing precipitation is occurring, or is forecast to occur, over a marine area.

Special Marine Warnings can be issued for any other weather-related phenomena which may result in a hazardous impact on local marine operations. For example, a marine forecaster may decide to issue a Special Marine Warning when an extended period of freezing precipitation is forecast over a marine area that may result in hazardous icing conditions on marine infrastructure.

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Ice Warnings

Ice Warnings are issued by the Canadian Ice Service (CIS), which is a specialized forecast centre within Environment Canada that deals specifically with providing information about ice in Canada’s navigable waters. Ice Warnings are included in the Ice Forecast bulletins issued by the CIS and are conveyed using the keywords “in effect.” 

Ice Warnings are designed to alert mariners to hazardous ice conditions that have already developed, or are forecast to develop, either locally or throughout the entire marine area under the warning. Ice Warnings are issued for specific ice conditions (Rapid Closing of Coastal Leads and Ice Pressure) and non-specific ice conditions (Special Ice) which may be hazardous to navigation or marine operations.

Rapid Closing of Coastal Leads Warnings

Rapid Closing of Coastal Leads Warnings are issued when the forecast combination of winds and ocean currents will result in the movement of pack ice rapidly closing any open waterways, known as leads, along the affected coastal sections.

Coastal leads can become blocked by six tenths or more of greywhite or older ice within a 12-hour period. Rapid Closing of Coastal Leads Warnings are relevant to all marine interests and can be issued for all coastal marine areas that have an ice forecast.

Ice Pressure Warnings

Ice Pressure Warnings are issued when a prolonged period of strong winds are forecast, which would cause ice pressure within the ice pack or along the coast.

Strong ice pressure could cause ships to lose the ability to navigate freely and could push ships towards potentially hazardous areas.  Ice Pressure Warnings are relevant to all marine interests and can be issued for all marine areas that have an ice forecast.

Special Ice Warnings

All other non-specified ice conditions that may warrant a warning being issued will be covered in a Special Ice Warning. Special Ice Warnings are relevant to all marine interests and can be issued for all marine areas that have an ice forecast.

A Special Ice Warningis issued for ice conditions that may be hazardous to marine operations. For example, a Special Ice Warning may be issued when ice is in an area at a time when ice is not usually there.

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