Photo: P199 · CC BY-SA 3.0South Glengarry is on Canada’s flood inventory: 7 listed, led by Raisin Region Conservation Authority
Around South Glengarry, wildfire is practically absent from the record: 0% within 25 km since 1986, 0.000% a year. Earthquakes add more: NRCan’s model puts building losses at $0.20 a year per $1,000 of value, against $0.030 for the typical town. About as many homes carry radon around South Glengarry as elsewhere, 6.1% over the guideline where the typical town has 6.6%. Hazard risk gives South Glengarry a grade of C, from earthquakes and radon alone.
What stands out about South Glengarry’s hazards
For South Glengarry, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What South Glengarry faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
South Glengarry grades C for hazard risk
Risk averages earthquakes and radon; wildfire joins only where it pulls the average down, so a town like South Glengarry with little fire nearby would get no credit for it.
Its place: #835 of 866 in Ontario and #2,073 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Wildfire is rare near South Glengarry: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where South Glengarry’s residents live, and the fuel next to their homes.
Fire claims 0.000% of the land around South Glengarry each year, a low band, with the typical Canadian town at 0.000%.
Since 1986 the nearest fire to South Glengarry’s homes came within 19 km, never inside 5 km.
6.3% of the land within 5 km of South Glengarry is forest fuel, close to the 5.1% within 25 km.
Shares of land within 5 and 25 km of populated blocks: burned at least once in 1986–2025 (CWFIS burned-area composite), forest fuel and grass (fire behaviour fuel types, 2026, 250 m grid).
Burn rate a year, towns in Ontario · highest of 871
Sioux Lookout has the highest burn rate in Ontario, 0.16% a year; around South Glengarry, as around 638 of the 871 towns, it rounds to zero.
Each bar: the yearly average share of land within 25 km of a town’s homes that burned, 1986–2025 (CWFIS); the seven highest towns of 2,500 people or more.
Like most of Canada’s 2,610 towns (92%), South Glengarry is in the low band, with a burn rate of zero to three decimals; 7.5% rank higher.
Bands of the yearly burn rate: low under 0.05%, moderate under 0.25%, high under 1%, very high 1% or more; towns of 2,500 people or more.
Fire danger and active fires (CWFIS)
Canadian Wildland Fire Information System: National Burned Area Composite 1986–2025 and fire behaviour fuel types (2026), Natural Resources Canada. Measured within 25 km and 5 km of each populated dissemination area; past fire, not a forecast.
Flooding around South Glengarry is mapped in 7 studies, the newest by Raisin Region Conservation Authority
Flood studies whose area touches South Glengarry, from NRCan’s inventory, each linked to its owner.
7 studies on the inventory touch South Glengarry, the newest Raisin Region Conservation Authority’s from 2020, and their areas can be large, so they say maps exist, not that the town floods.
| Study | By | Year | Status |
|---|---|---|---|
| Raisin River and St. Lawrence River Floodplain Mapping Update | Raisin Region Conservation Authority | 2020 | final · not public |
| St. Lawrence River Floodline Re-Mapping Study | Raisin Region Conservation Authority | 1994 | final · not public |
| Gray's Creek Flood Plain Mapping Study | Raisin Region Conservation Authority | 1988 | final · not public |
| Flood Plain Mapping Study - Main and North Branches Raisin River | Raisin Region Conservation Authority | 1987 | final · not public |
| South Branch - Raisin River Flood and Fill Line Mapping | Raisin Region Conservation Authority | 1984 | final · not public |
| Delisle River Flood Plain Mapping and Water Management Study | Raisin Region Conservation Authority | 1983 | final · not public |
| Riviere au Baudet Flood Plain Mapping and Minor Channel Improvements Study | Raisin Region Conservation Authority | 1977 | final · not public |
Towns with a flood study on file
Flood maps are common in Ontario: 69% of towns have one, against 58% nationally, and South Glengarry is among them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The busiest decade for flood studies around South Glengarry was the 1980s (4 of 7); they run from the 1970s to the 2020s.
Study dates as the NRCan inventory lists them, one count per study touching South Glengarry.
Flood studies don’t enter the grade; they are listed so you can open the official map for South Glengarry.
The inventory’s own caution (NRCan): “The Canada Flood Map (CFM) does not include every flood hazard map in Canada and may be incomplete or contain inaccuracies. It should not be relied upon as the official source of flood mapping information. Furthermore, if a map appears to be missing, this does not necessarily mean that the area has never been mapped. For the official version of a map, updated information, or confirmation of applicable regulations, please contact the local authority responsible for flood mapping.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Shaking is South Glengarry’s costliest hazard: $0.20 a year per $1,000
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
The typical town loses $0.030 a year to shaking; South Glengarry loses $0.20, 6.8 times as much.
Shaking damage a year per $1,000 of building value
South Glengarry’s $0.20 tops the median in Ontario, $0.043, though Alexandria reaches $0.21.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
Few of Canada’s 2,611 towns face more earthquake damage than South Glengarry: 8.4% of them.
Each column: the share of Canada’s towns of 2,500 people or more in that range of yearly loss per $1,000 (NRCan, 2022).
What a quake does after the shaking, fire, landslides, tsunami, falls outside NRCan’s figure for South Glengarry.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
6.1% of homes tested around South Glengarry are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
South Glengarry’s area sits close to the typical Canadian town: 6.1% over the guideline, against 6.6%. South Glengarry doesn’t get its own radon tests figures; the ones here come from the The Eastern Ontario Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
More homes top the guideline around South Glengarry (6.1%) than in the typical town in Ontario (4%); 1% went over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
A middling share of high tests puts South Glengarry with 37% of Canada’s 2,611 towns, below 26% of them.
Each bar: the share of Canada’s towns of 2,500 people or more whose survey area had that share of tests over 200 Bq/m³.
A low area share in South Glengarry doesn’t clear a house, nor does a high one condemn it: test.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in South Glengarry
Alerts for South Glengarry come from Environment and Climate Change Canada and, for emergencies, Alert Ready.
| Alert | What it means |
|---|---|
| Warning | Severe weather is happening or about to: act now. |
| Watch | Conditions favour severe weather: be ready. |
| Advisory | Weather that is less severe but could disrupt the day. |
| Special weather statement | Unusual weather worth knowing about. |
| Special air quality statement | Poor air, often wildfire smoke. |
Evacuation orders for South Glengarry come from the municipality or the province, while CWFIS maps fire danger every day.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around South Glengarry
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| South Glengarry | Low | $0.20 | 6.1% | Yes |
| Akwesasne 2,562 · 13 km | Low | $0.22 | 8.2% | None listed |
| Cornwall 54,346 · 15 km | Low | $0.20 | 6.1% | Yes |
| Akwesasne (Part) 59 1,947 · 16 km | Low | $0.14 | 6.1% | Yes |
| Saint-Anicet 2,854 · 17 km | Low | $0.19 | 8.2% | None listed |
Saint-Anicet burns a little more than South Glengarry, in the same low band (low here).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what South Glengarry faces
What to do about the hazards South Glengarry faces, and what to ask before you buy.
- Test for three months in winter.
- Over 200 Bq/m³: fix it.
- Kits are cheap; pros test too.
- Never drive through floodwater.
- Move papers and medicines upstairs.
- Ask whether your street is mapped.
- Drop, cover and hold on.
- Strap the water heater down.
- Keep 72 hours of supplies.
- Has it had a radon test?
- Check the address on the flood map.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, South Glengarry takes its 2007 health region’s share.
- Wildfire counts one way. Burned land within 25 km of where people live, averaged over 1986–2025 and checked for fuel near homes, is the measure; it looks back, not ahead, and only ever counts against South Glengarry.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, South Glengarry’s included.
- Flood studies aren’t flood zones. The flood inventory points to maps; it is incomplete and not the official source, so ask the municipality about any street in South Glengarry.
Questions about flooding and hazards in South Glengarry
How big is the earthquake risk in South Glengarry?
Expected earthquake damage in South Glengarry comes to $0.20 a year for each $1,000 that buildings are worth.
Is radon a problem in South Glengarry?
Around South Glengarry, 99 survey homes were tested and 6.1% came in over 200 Bq/m³, a guide to the area, not to any one home.
Does South Glengarry flood?
The inventory lists a study touching South Glengarry; whether a given street floods is on that map, not in the grade.
How is South Glengarry’s Hazard risk Grade worked out?
South Glengarry’s Hazard risk grade is C, built on earthquakes and radon with a one-sided wildfire input.
Is South Glengarry at risk of wildfire?
Fire has reached 0% of the land around South Glengarry since 1986 (last in 2024); at low, it neither helps nor hurts the grade.
Seismic risk: Natural Resources Canada. Radon: Health Canada. Wildfire: Canadian Wildland Fire Information System. Flood studies: Natural Resources Canada, Canada Flood Map Inventory. Contains information licensed under the Open Government Licence – Canada.
Sources: NRCan, Canada’s Seismic Risk Model 2022 · Health Canada, Cross-Canada Survey of Radon Concentrations in Homes · CWFIS, National Burned Area Composite and FBP fuel types · NRCan, Canada Flood Map Inventory. Under the Statistics Canada Open Licence.
Adapted from Statistics Canada (Census of Population 2021, population estimates 2025, 2021 census boundaries) under the Statistics Canada Open Licence; this does not constitute an endorsement by Statistics Canada. Neighbourhood names in some cities © OpenStreetMap contributors (ODbL).