Photo: P199 · Public domainSt.-Charles’ hazards at a glance: a low wildfire record and 5.2% of area homes over the radon guideline
Little of the land around St.-Charles has burned: 0.2% within 25 km since 1986, or 0.005% a year. NRCan expects $0.029 of shaking damage a year per $1,000 of buildings in St.-Charles, near the typical $0.030. St.-Charles grades A− for hazard risk, with wildfire counted against it.
What stands out about St.-Charles’s hazards
Four national sources, each read for St.-Charles: earthquakes, radon, past fires and flood studies.
What St.-Charles faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in St.-Charles: A−
Seismic risk and radon set St.-Charles’ grade, wildfire can drag it down, and flood mapping stays out of it.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. Small fires and grass fires are largely missing from the national burned-area record.
Few fires near St.-Charles: 0% within 5 km, 0.2% within 25 km
Fires mapped since 1986 around where St.-Charles’ residents live, and the fuel next to their homes.
The yearly burn rate around St.-Charles is 0.005%, low beside 0.000% for the typical Canadian town.
St.-Charles’ homes have had no fire within 5 km since 1986; the closest was 17 km away.
The nearer ring around St.-Charles is less wooded (15% forest fuel) than the land out to 25 km (40%).
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 872
At 0.005% a year, St.-Charles is near the top in Ontario: 43rd of 872, behind Sioux Lookout (0.16%).
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.
St.-Charles is in the low band with 92% of Canada’s 2,610 towns; 7.5% sit in moderate or 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.
No flood study is listed for St.-Charles
Flood studies whose area touches St.-Charles, from NRCan’s inventory, each linked to its owner.
An empty entry for St.-Charles on the inventory isn’t proof of safety; ask locally for flood maps.
Towns with a flood study on file
Missing from a well-mapped province: St.-Charles has no study, where 69% of towns in Ontario have one against 58% nationally.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood studies don’t enter the grade; they are listed so you can open the official map for St.-Charles.
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.”
Expected shaking damage in St.-Charles: $0.029 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.
At $0.029 per $1,000, St.-Charles’ earthquake risk is the typical Canadian town’s $0.030.
Shaking damage a year per $1,000 of building value
Earthquake risk in Ontario peaks in Alexandria ($0.21); St.-Charles, at $0.029, is below the median of $0.043.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
St.-Charles’ earthquake risk lands near the centre of Canada’s range; 51% of the 2,611 towns are higher.
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).
The loss is to St.-Charles’ buildings alone, from ground shaking; infrastructure and secondary hazards are left out.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Some radon around St.-Charles: 5.2% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Area-wide: radon tests, counted over the Sudbury and District Health Unit
At 5.2% over the guideline, the area around St.-Charles is about level with the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around St.-Charles, 5.2% of tests were over 200 Bq/m³ and 1% over 600, against a median of 4% in Ontario.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
37% of Canada’s 2,611 towns share St.-Charles’ band of 5 to 10%; 26% sit higher.
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.
Basements, soil and how a house is sealed decide its radon, so in St.-Charles only a test can say.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for St.-Charles
Alerts for St.-Charles 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. |
Fire danger and active fires near St.-Charles are mapped daily by the Canadian Wildland Fire Information System; evacuation orders come from the municipality or province.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around St.-Charles
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| St.-Charles | Low | $0.029 | 5.2% | None listed |
| Markstay-Warren 2,990 · 15 km | Low | $0.028 | 5.2% | None listed |
St.-Charles’ low band tops its neighbours; Markstay-Warren is next (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what St.-Charles faces
Practical steps for St.-Charles’ hazards, most pressing first.
- 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.
- Clear needles and wood nearby.
- Keep a grab-and-go bag ready.
- In smoke, stay in; filter air.
- Has it had a radon test?
- Ask the municipality for flood maps.
- Are flood and wildfire insured?
What this data can and can’t tell you
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of St.-Charles’ homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- 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 St.-Charles.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, St.-Charles takes its 2007 health region’s share.
- Earthquakes are modelled. Shaking damage is modelled from the ground, the buildings and the odds of each quake, and published for whole subdivisions such as St.-Charles’.
Questions about flooding and hazards in St.-Charles
How is St.-Charles’s Hazard risk Grade worked out?
St.-Charles’ Hazard risk grade is A−, built on earthquakes and radon with a one-sided wildfire input.
Is St.-Charles at risk of wildfire?
Not much by Canadian standards: St.-Charles’ band is low, with 0.2% of the land within 25 km burned since 1986 (last in 2022), so wildfire doesn’t change its grade.
Is radon a problem in St.-Charles?
5.2% of the 97 homes Health Canada tested around St.-Charles topped the guideline; your own house needs its own test.
How big is the earthquake risk in St.-Charles?
Expected earthquake damage in St.-Charles comes to $0.029 a year for each $1,000 that buildings are worth.
Does St.-Charles flood?
No study on Canada’s Flood Map Inventory covers St.-Charles (0), which doesn’t mean it has never been mapped, so ask the municipality.
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).