Weather warning index indicator: data sources and methods, chapter 3


3. Data

3.1 Data source

The data sources for the Weather Warning Index indicator include timeliness performance information for the identified six severe weather warning types. This information is compiled by comparing warnings issued by Environment and Climate Change Canada against severe weather reports submitted by the public and data collected by Environment and Climate Change Canada's observation network.

Timeliness statistics reflect the average lead time and target lead time for each of the six warning types, as determined by the warning performance targets (see Table 5, Section 4). Accuracy statistics are expressed in terms of the extremal dependency index (EDI), which incorporates the number of hits, misses and false alarms for each of the six warning types.

These statistics are compiled by Environment and Climate Change Canada from available meteorological observations, archived warning bulletins and existing verification procedures.

3.2 Spatial coverage

Information reported in selected geographic regions for each warning group is used in calculating the index. These selected geographic regions are representative of Canada's climate and are areas that regularly have sufficient event data against which to compare severe weather warnings.

Public forecast regions with those used in the Weather Warning Index highlighted - rainfall, snowfall, freezing rain and wind warnings

Map of Canada - See long description below
Long description

The map of Canada shows the public forecast regions used in the Weather Warning Index for rainfall, snowfall, freezing rain and wind warnings. These regions are highlighted on the map. Les Suêtes wind warnings are only issued for one forecast region in Nova Scotia, and Wreckhouse Winds warnings are only issued for one region in Newfoundland and Labrador. A complete list of the regions can be found in Table 2.

Note: Data from public forecast regions that were substituted is used in historical data up to the year of substitution. Some regions are not visible at the national scale. See Table 2 for the complete list.
Source: Environment and Climate Change Canada (2016) Forecast Regions of Canada. Meteorological Service of Canada - Integrated Planning and Performance Management Division.

Table 2. Public forecast regions used in the Weather Warning Index for rainfall, snowfall, freezing rain and wind warnings
Pacific and Yukon Prairie and Northern Ontario Quebec Atlantic
Metro Vancouver City of Winnipeg Windsor - Essex - Chatham-Kent Metro Montréal - Laval Saint John and County
Fraser Valley - West Including Abbotsford Thompson - Nelson House - Split Lake London - Middlesex Eastern Townships Moncton and Southeast New Brunswick
East Vancouver Island City of Regina City of Hamilton Québec City Halifax Metro and Halifax County West
Greater Victoria City of Saskatoon City of Toronto Saguenay Queens County PEI (Charlottetown)
North Coast - Inland Sections Prince Albert - Shellbrook - Spiritwood - Duck Lake City of Ottawa Lac-Saint-Jean Sydney Metro and Cape Breton County
Central Okanagan - Including Kelowna City of Calgary North Bay - West Nipissing Rimouski - Mont Joli Inverness County - Mabou and north (Les Suêtes, wind only)
West Kootenay City of Edmonton - St. Albert - Sherwood Park Greater Sudbury and Vicinity Forillon National Park - Gaspé - Percé

2009 to 2011: St. Georges

Since 2012: Channel-Port aux Basques and vicinity

(Wreckhouse, wind only)

Prince George Yellowknife Region Sault Ste. Marie - Superior East Abitibi Gander and vicinity
BC North Peace River Resolute City of Thunder Bay Sept-Iles - Port-Cartier St. John's and vicinity
Whitehorse Iqaluit

2009 to 2013: Kapuskasing - Hearst

Since 2014: Timmins - Cochrane

Blanc Sablon Upper Lake Melville (known as Goose Bay and Vicinity before 2012)
- - - Kuujjuaq Labrador City and Wabush

Public forecast regions with those used in the Weather Warning Index highlighted - severe thunderstorm warnings

Map of Canada  - see long description below
Long description

The map of Canada shows the public forecast regions used for the severe thunderstorm warning component of the Weather Warning Index. These regions are highlighted on the map. A complete list of the regions can be found in Table 3.

Note: Data from public forecast regions that were substituted is used in historical data up to the year of substitution. Some regions are not visible at the national scale. See Table 3 for the complete list.
Source: Environment and Climate Change Canada (2016) Forecast Regions of Canada. Meteorological Service of Canada - Integrated Planning and Performance Management Division.

Table 3. Public forecast regions used in the Weather Warning Index for severe thunderstorm warnings
Pacific and Yukon Prairie and Northern Ontario Quebec Atlantic
Metro Vancouver City of Winnipeg Windsor - Leamington - Essex County Montréal Island area Saint John and County
Fraser Valley-West including Abbotsford City of Brandon London - Parkhill - Eastern Middlesex County Huntingdon area Moncton and Southeast New Brunswick
East Vancouver Island R.M. of Dauphin including Sifton and Valley River City of Hamilton Saint-Hyacinthe - Acton Vale area Halifax Metro and Halifax County West
Greater Victoria City of Regina City of Toronto Rawdon - Joliette area Queens County PEI (Charlottetown)
North Coast - Inland Sections City of Saskatoon Ottawa North - Kanata - Orléans Lachute area Sydney Metro and Cape Breton County
Central Okanagan - Including Kelowna City of Prince Albert North Bay - Powassan - Mattawa Mont-Tremblant - Sainte Agathe area Oromocto and Sunbury County
West Kootenay City of Calgary Greater Sudbury and vicinity Papineau-Labelle Reserve area Gander and vicinity
Prince George City of Edmonton - St. Albert - Sherwood Park Sault Ste. Marie - St. Joseph Island Val D'Or - Louvicourt area St. John's and vicinity
BC North Peace River City of Lethbridge City of Thunder Bay Granby - Waterloo area Upper Lake Melville (known as Goose Bay and vicinity before 2012)
Whitehorse County of Grande Prairie near Grande Prairie and Wembley

2009 to 2013: Kapuskasing - Hearst - Smooth Rock Falls

Since 2014: Timmins - Cochrane - Iroquois Falls

Quebec area Labrador City and Wabush
- - - Alma - Desbiens area -

Marine forecast areas with those used in the Weather Warning Index highlighted - marine gale warnings

Map of Canada - See long description below
Long description

The map of Canada shows all marine forecast areas. The marine forecast areas used for the marine gale warning component of the Weather Warning Index are also highlighted on the map. A complete list of the areas can be found in Table 4.

Note: Data from marine forecast areas that were substituted is used in historical data up to the year of substitution. Some areas are not visible at the national scale. See Table 4 for the complete list.
Source: Environment and Climate Change Canada (2016) Canadian Marine Warning Program. Meteorological Service of Canada - Integrated Planning and Performance Management Division.

Table 4. Marine forecast areas used in the Weather Warning Index for marine gale warnings
Pacific and Yukon Prairie and Northern Ontario Quebec Atlantic
Strait of Georgia - south of Nanaimo Great Slave Lake Basin Western Lake Superior

2009 to 2012: Donnacona to Isle-aux-Coudres

Since 2013: Beauport to L'Isle-aux-Coudres

2009 to 2014: Georges Bank

Since 2015: Browns Bank

Strait of Georgia - north of Nanaimo Tuktoyaktuk Eastern Lake Superior Tadoussac to Pointe à Michel Sable
Juan de Fuca Strait - East Entrance Frobisher Bay Western Lake Erie Pointe à Michel to Pointe-des-Monts Gulf - Magdalen
West Vancouver Island North West Brevoort - southern half Eastern Lake Erie Pointe-des-Monts to Anticosti - southern half Northeast Gulf
Queen Charlotte Sound - Western half Barrow Western Lake Ontario - Southwest Coast
Hecate Strait - Northern Half Lake Manitoba Eastern Lake Ontario - Northeast Coast
- Lake Winnipeg - South Basin - - Northern Grand Banks
- Lake Winnipeg - North Basin - - -

3.3 Temporal coverage

To reduce volatility from year to year, a three-year moving average is used for reporting purposes. The latest index uses data from calendar years 2013, 2014 and the most recent year, 2015. This is the fifth iteration of the index. The first iteration calculated a three-year moving average using 2009, 2010 and 2011 data, the second iteration used 2010, 2011 and 2012 data, the third iteration used 2011, 2012 and 2013 data and the fourth iteration used 2012, 2013 and 2014 data. The index is updated annually. Each spring, a value is calculated for the previous calendar year using available information.

3.4 Data completeness

Data for selected geographic regions for each warning type are used in calculating the index. These regions are representative of Canada's climate and are areas that regularly have sufficient event data against which to compare severe weather warnings.

3.5 Data timeliness

Data are available for each calendar year by the spring of the following year.

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