Legislation in New Brunswick, Nova Scotia and Prince Edward Island dictates that governments “make surveys and studies to identify and record actual and potential hazards which may cause an emergency or disaster” (NB Emergency Measures Act, 1978, 7b; NS Emergency Measures Act, 1990, 8b; and PEI Emergency Measures Act, 1988, 6c). Similarly, Newfoundland and Labrador’s Emergency Measures Act (1990, 6.1) states that “the council of a municipality may by resolution establish a committee and adopt a plan to deal with all matters relating to emergency measures within the boundaries of the municipality.” Information provided on the Atmospheric Hazards in the Atlantic Region website is intended to assist municipalities and provincial governments assess their risk from atmospheric hazards by providing background information and map data for the Atlantic region. This website was created by the Adaptation and Impacts Research Division of Environment Canada.

Atmospheric Hazards in Atlantic Canada

Atmospheric hazards that frequently impact the four Atlantic Provinces include winter hazards, summer hazards, and hazards that are not specific to any one season. Snow storms are a major winter hazard and on this website are divided into snowfall, blowing snow, and blizzard events. Heavy snowfalls may limit mobility in a region and blowing snow and blizzards can make any travel dangerous as visibility conditions deteriorate and temperatures fall. Freezing precipitation poses a threat to critical infrastructure and transportation as surfaces become coated in ice causing slippery conditions and added pressure on structures and communication systems.

Extreme hot and cold temperatures may pose a threat to people if they are exposed to them for prolonged periods of time or they cannot physically adjust to the conditions. Extreme cold combined with high winds results in extreme wind chill. Similarly, humidity compounded with extreme heat, causes extreme humidex values. Factors to consider in an analysis of the threat from extreme temperatures are the extreme maximum and minimum temperatures, the extreme maximum humidex and minimum wind chill values, the frequency of occurrence, plus the duration of an event.

Hurricanes frequently track south of the Atlantic Provinces occasionally crossing the Maritimes or Newfoundland. Thunderstorms are most common in New Brunswick in the summer when storm systems move in from the continental United States, although south of Nova Scotia is a very active area for lightning strikes. Storm surge may occur in conjunction with hurricanes in the fall or with winter storms. Fog is very prevalent in Atlantic Canada and must be considered in a risk assessment because of the threat to transportation, be it land, marine, or air.

Purpose of Website

Costs from atmospheric hazards continue to rise as the population becomes more concentrated in urban areas, more reliant on critical infrastructures, and less able to cope with the climatic extremes that occur in the region. This website aims to assist local and provincial governments plan for emergencies in their jurisdictions by providing information on the types of atmospheric hazards common to the region and the climatology of those events. Stakeholders may assess their risks through analysis of the maps displayed on the website or through use of the raw data provided within.

Information on Website

Information on this website is divided according to hazard and the season that it is commonly associated with. Some hazards may occur at any time and thus are filed under all season hazards. There is cross-over in some of the categories. For example, lightning is listed separately but is also associated with thunderstorms. Likewise, storm surge may be caused by a hurricane or another mid-latitude storm. Maps on this website show information that has been extrapolated from point data in order to estimate conditions at locations removed from climate stations. While this may be a controversial decision in terms of climatology, employing this technique assists stakeholders assess their risk without having to complete their own estimation from point source data. Data tables are provided so interested parties can examine the raw data. Point maps are used when it is not possible to extrapolate data with any degree of confidence.

Downloading Information

Maps are shown in two formats, the screen display and print quality. Maps labelled "Screen display" can be viewed directly from your web browser. Maps labelled "Download" link to large images, which may take considerable time to view or download. It is recommended that these images be saved directly to the user's computer, and then opened in a suitable viewing program to permit zooming and a more detailed examination of the maps. To download these files, right click on the image link and select "Save Target as...".