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Data Sources and Methods for the Weather Warning Index

Data

3.1 Data source

The data sources for the Weather Warning Index include timeliness performance information for the identified six severe weather warning types. This information is compiled by comparing warnings issued by Environment Canada against severe weather reports submitted by the public and data collected by Environment 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 our warning performance targets. Accuracy statistics reflect 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 Canada from available meteorological observations, archived warning bulletins and existing verification procedures. This information is available in the quarterly and annual reports from the Meteorological Service of Canada (MSC) warning program prepared by the Performance Management Division of the Business Policy Directorate.

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

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

Note: Some public forecast regions are not visible at the national scale. See Table 1 for the complete list.
Source: Environment Canada (2013) Public Forecast Regions of Canada. Meteorological Service of Canada - Performance Management Systems Division.

Table 1: Public forecast regions used in the Weather Warning Index for rainfall, snowfall, freezing rain and wind warnings
Pacific and YukonPrairie and NorthernOntarioQuebecAtlantic
Metro VancouverCity of WinnipegWindsor – Essex – Chatham-KentMetro Montreal - LavalSaint John and County
Fraser Valley- West Including AbbotsfordThompson – Nelson House – Split LakeLondon - MiddlesexQuebecMoncton and Southeast New Brunswick
East Vancouver IslandCity of ReginaCity of HamiltonSaguenayHalifax Metro and Halifax County West
Greater VictoriaCity of SaskatoonCity of TorontoRimouski – Mont JoliCharlottetown (Queens County P.E.I.)
North Coast – Inland SectionsPrince Albert – Shellbrook – Spiritwood – Duck LakeCity of OttawaForillon National Park - Gaspé - PercéSydney Metro and Cape Breton County
Central Okanagan – Including KelownaCity of CalgaryNorth Bay – West NipissingAbitibiInverness County (Les Suetes Wind only)
West KootenayCity of EdmontonGreater Sudbury and VicinityChibougamauSt. Georges (Wreckhouse Wind only)
Prince GeorgeYellowknife RegionSault Ste. Marie – St. Joseph IslandSept-Iles – Port-CartierGander and Vicinity
BC North Peace RiverResoluteCity of Thunder BayBlanc SablonSt. John’s and Vicinity
WhitehorseIqaluitKapuskasing - HearstFermontGoose Bay and Vicinity
---KuujjuaqLabrador City and Wabush

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

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

Note: Some public forecast regions are not visible at the national scale. See Table 2 for the complete list.
Source: Environment Canada (2013) Public Forecast Regions of Canada. Meteorological Service of Canada - Performance Management Systems Division.

Table 2: Public forecast regions used in the Weather Warning Index for severe thunderstorm warnings
Pacific and YukonPrairie and NorthernOntarioQuebecAtlantic
Metro VancouverCity of WinnipegWindsor – Essex – Chatham-Kent
(Windsor - Leamington -Essex County)
Montréal métropolitain – Laval
(l’ile de Montréal)
Saint John and County
Fraser Valley- West Including AbbotsfordBrandon – Carberry – Treherne
(City of Brandon)
London – Middlesex
(London - Parkhill - Eastern Middlesex County)
Vaudreuil - Soulanges – Huntingdon
(Huntingdon)
Moncton and Southeast New Brunswick
East Vancouver IslandDauphin – Roblin – Winnipegosis
(R.M. of Dauphin including Sifton and Valley River)
City of HamiltonVallée du Richelieu - Saint-Hyacinthe
(Saint-Hyacinthe – Acton Vale)
Halifax Metro and Halifax County West
Greater VictoriaCity of ReginaCity of TorontoLanaudière
(Rawdon – Joliette)
Charlottetown (Queens County P.E.I.)
North Coast – Inland SectionsCity of SaskatoonCity of Ottawa
(Ottawa North - Kanata – Orléans)
Lachute - Saint-Jérôme
(Lachute)
Sydney Metro and Cape Breton County
Central Okanagan – Including KelownaPrince Albert – Shellbrook – Spiritwood – Duck Lake
(City of Prince Albert)
North Bay – West Nipissing
(North Bay - Powassan – Mattawa)
Laurentides
(Mont-Tremblant – Sainte Agathe)
Oromocto and Sunbury County
West KootenayCity of CalgaryGreater Sudbury and VicinityHaute-Gatineau - Lièvre – Papineau
(Reserve Papineau-Labelle)
Gander and Vicinity
Prince GeorgeCity of EdmontonSault Ste. Marie – Superior East
(Sault Ste. Marie – St. Joseph Island)
Abitibi
(Val D’Or – Louvicourt)
St. John’s and Vicinity
BC North Peace RiverLethbridge – Taber – Milk River
(City of Lethbridge)
City of Thunder BayEstrie
(Granby – Waterloo)
Goose Bay and Vicinity
WhitehorseGrande Prairie – Beaverlodge – Valleyview
(Co. of Grande Prairie near Grande Prairie and Wembley)
Kapuskasing - Hearst
(Kapuskasing - Hearst -Smooth Rock Falls)
QuébecLabrador City and Wabush
---Lac Saint-Jean
(Alma – Desbiens)
-

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

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

Note: Some marine forecast areas are not visible at the national scale. See Table 3 for the complete list.
Source: Environment Canada (2013) Meteorological Service of Canada - Performance Management Systems Division

Table 3: Marine forecast areas used in the Weather Warning Index for gale warnings
Pacific and YukonPrairie and NorthernOntarioQuebecAtlantic
Strait of Georgia – south of NanaimoGreat Slave Lake BasinWestern Lake SuperiorDonnacona to Isle-aux-CoudresGeorges Bank
Strait of Georgia – north of NanaimoTuktoyaktukEastern Lake SuperiorTadoussac to Pointe-des-MontsSable
Juan de Fuca Strait – East EntranceFrobisher BayNorthern Lake HuronPointe-des-Monts to Anticosti – southern halfGulf – Magdalen
West Vancouver Island NorthWest Brevoort – southern halfSouthern Lake Huron-Northeast Gulf
Queen Charlotte Sound – western halfBarrowWestern Lake Erie-Southwest Coast
Hecate Strait – Northern HalfLake ManitobaEastern Lake Erie-Northeast Coast
-Lake Winnipeg – South BasinWestern Lake Ontario-Northern Grand Banks
-Lake Winnipeg – North BasinEastern Lake Ontario--

3.3 Temporal coverage

To reduce volatility from year to year, a three-year moving average is used for reporting purposes. The index uses data from calendar years 2010, 2011 and the most recent year 2012. This is the second iteration of the index. The first iteration calculated a three-year moving average using data from 2009, 2010 and 2011.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 by the end of February of the following year. The index will be updated each year in the spring with these data.