St. Clair’s hazards at a glance: a low wildfire record and 5% of area homes over the radon guideline
Around St. Clair, wildfire is practically absent from the record: 0% within 25 km since 1986, 0.000% a year. For earthquakes St. Clair is middling, $0.044 a year per $1,000 against $0.030 for the typical town. Hazard risk gives St. Clair a grade of B+, from earthquakes and radon alone.
What stands out about St. Clair’s hazards
Four national sources, each read for St. Clair: earthquakes, radon, past fires and flood studies.
What St. Clair 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. Clair: B+
The grade weighs St. Clair’s seismic risk and radon equally, and wildfire is one-sided: a high band counts against a town, a low one earns nothing.
Its place: #494 of 866 in Ontario and #1,255 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Small fires and grass fires are largely missing from the national burned-area record.
Wildfire is rare near St. Clair: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where St. Clair’s residents live, and the fuel next to their homes.
At 0.000% of the land a year, St. Clair’s burn rate is in the low band; the typical Canadian town sees 0.000%.
Around St. Clair the forest is thin or far off: 0.1% of the land within 5 km and 1.2% within 25 km is forest fuel.
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
Among the 871 towns in Ontario, Sioux Lookout burns fastest (0.16% a year); St. Clair is with the 638 near 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.
92% of Canada’s 2,610 towns are in the low band and 7.5% above it; St. Clair is among the many where the yearly burn rate rounds to zero.
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.
The flood map inventory lists nothing for St. Clair
Flood studies whose area touches St. Clair, from NRCan’s inventory, each linked to its owner.
The inventory has nothing for St. Clair, but a local or conservation-authority map may still exist.
Towns with a flood study on file
St. Clair has no flood study on file, though 69% of towns in Ontario do (Canada: 58%).
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Nothing here counts toward Risk; the studies are pointers to the maps their owners keep for St. Clair.
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.”
Ordinary seismic risk in St. Clair: $0.044 per $1,000 of buildings a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
Earthquake losses in St. Clair, $0.044 per $1,000, are in line with the typical $0.030 (1.5 times).
Shaking damage a year per $1,000 of building value
About level with the typical town in Ontario: St. Clair’s $0.044 against $0.043; 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.
32% of Canada’s 2,611 towns expect more shaking damage than St. Clair, which places it in the upper third.
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).
Roads, pipes and bridges aren’t in St. Clair’s figure, nor landslides or tsunami: it is buildings and shaking.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean). · Not measured by town: earthquake risk (the city of Hamilton)
Some radon around St. Clair: 5% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
St. Clair’s area, at 5%, is close to the 6.6% of the typical Canadian town.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
The median in Ontario is 4% over 200 Bq/m³; the survey area around St. Clair has 5%.
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 St. Clair 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.
Basements, soil and how a house is sealed decide its radon, so in St. Clair only a test can say.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Radon tests: one figure for all of the City of Hamilton Health Unit
Weather and fire alerts for St. Clair
Environment and Climate Change Canada issues the weather alerts for St. Clair; Alert Ready carries the urgent ones to phones, radio and TV.
| 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. |
Smoke and fire warnings for St. Clair come through Environment Canada and Alert Ready; the fire map is CWFIS’s.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around St. Clair
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| St. Clair | Low | $0.044 | 5% | None listed |
| Stinson 3,969 · 0.7 km | Low | $0.044 | 5% | None listed |
| Gibson 7,581 · 0.8 km | Low | $0.044 | 5% | None listed |
| Blakeley 3,151 · 1.1 km | Low | $0.044 | 5% | None listed |
| Eastmount 4,496 · 1.1 km | Low | $0.044 | 5% | None listed |
| Inch Park 4,065 · 1.1 km | Low | $0.044 | 5% | None listed |
| Landsdale 7,681 · 1.1 km | Low | $0.044 | 5% | None listed |
None of the places around has more fire nearby than St. Clair (low); Stinson comes closest (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what St. Clair faces
What to do about the hazards St. Clair 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.
- 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
- Radon is a survey. Radon figures pool the survey’s home tests by area: postal areas once their boundaries arrive, the 2007 health region around St. Clair until then.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of St. Clair’s 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. Flood studies cover areas of every size, which is why the page lists them for St. Clair without grading them.
- 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. Clair’s.
Questions about flooding and hazards in St. Clair
How big is the earthquake risk in St. Clair?
About $0.044 a year per $1,000 of building value, NRCan’s long-run expectation for St. Clair.
Is St. Clair at risk of wildfire?
Hardly at all on record: 0% of the land within 25 km of St. Clair since 1986, a low band, though small grass fires aren’t mapped.
Does St. Clair flood?
With 0 studies on the inventory, St. Clair’s flood risk is unmapped nationally; check with the municipality before buying.
Is radon a problem in St. Clair?
Around St. Clair, 100 survey homes were tested and 5% came in over 200 Bq/m³, a guide to the area, not to any one home.
How is St. Clair’s Hazard risk Grade worked out?
St. Clair’s Hazard risk grade is B+, built on earthquakes and radon with a one-sided wildfire input.
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).