Photo: P199 · CC BY-SA 3.0Wildfire low, radon 8.6%: how St. Joseph stands on hazards
No wildfire is mapped within 25 km of St. Joseph’s homes since 1986 (0% of the land, 0.001% a year). Seismic risk runs low: $0.006 of expected damage per $1,000 of buildings a year, the typical town $0.030. St. Joseph grades A− for hazard risk, with wildfire counted against it.
What stands out about St. Joseph’s hazards
For St. Joseph, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What St. Joseph 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. Joseph: A−
Two inputs always count for St. Joseph, earthquakes and radon; the third, wildfire, counts only against a town.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Wildfire is rare near St. Joseph: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where St. Joseph’s residents live, and the fuel next to their homes.
Low by Canadian standards: 0.001% of the land a year around St. Joseph, 0.000% for the typical Canadian town.
Since 1986 the nearest fire to St. Joseph’s homes came within 14 km, never inside 5 km.
Forest fuel is denser close to St. Joseph (28% within 5 km) than further out (21% 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 872
St. Joseph ranks 83rd of the 872 towns in Ontario for burn rate, at 0.001% a year; Sioux Lookout leads with 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.
Beside 2,610 Canadian towns, St. Joseph reads low, with 92% of them; only 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.
The flood map inventory lists nothing for St. Joseph
Flood studies whose area touches St. Joseph, from NRCan’s inventory, each linked to its owner.
Canada’s Flood Map Inventory lists no study whose area touches St. Joseph, which doesn’t mean it has never been mapped.
Towns with a flood study on file
Missing from a well-mapped province: St. Joseph 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 is shown here, never graded: a study says where a map exists, not how many of St. Joseph’s homes stand in a flood zone.
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.”
Low seismic risk in St. Joseph: $0.006 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.
0.2 times the typical $0.030: St. Joseph’s $0.006 is low for Canada.
Shaking damage a year per $1,000 of building value
Earthquake risk in Ontario peaks in Alexandria ($0.21); St. Joseph, at $0.006, 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.
Most of Canada’s 2,611 towns (88%) face more earthquake damage than St. Joseph.
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).
Only shaking damage to buildings in St. Joseph is counted; landslides, liquefaction, tsunami and fire after a quake aren’t.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Radon about average around St. Joseph: 8.6% over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
The survey area of St. Joseph reads 8.6%, a shade from the typical Canadian town’s 6.6%. For radon tests, the only official count covers all of the The District of Algoma Health Unit, St. Joseph included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
St. Joseph’s area, at 8.6%, is above the median in Ontario (4%), and 1.1% of its tests passed 600 Bq/m³.
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. Joseph 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.
Neighbouring homes in St. Joseph can differ a lot; only a long-term test tells you about yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in St. Joseph
Environment and Climate Change Canada issues the weather alerts for St. Joseph; 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. |
In fire season, check CWFIS for danger and active fires around St. Joseph, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How St. Joseph’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| St. Joseph | Low | $0.006 | 8.6% | None listed |
| Laird 1,221 · 14 km | Low | $0.005 | 8.6% | None listed |
Among its neighbours St. Joseph has the most fire on record (low); Laird follows (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what St. Joseph faces
What to do about the hazards St. Joseph 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
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for St. Joseph without grading them.
- 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 St. Joseph.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, St. Joseph’s included.
- 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. Joseph until then.
Questions about flooding and hazards in St. Joseph
How is St. Joseph’s Hazard risk Grade worked out?
St. Joseph’s Hazard risk grade is A−, built on earthquakes and radon with a one-sided wildfire input.
Is radon a problem in St. Joseph?
Around St. Joseph, 93 survey homes were tested and 8.6% came in over 200 Bq/m³, a guide to the area, not to any one home.
Does St. Joseph flood?
With 0 studies on the inventory, St. Joseph’s flood risk is unmapped nationally; check with the municipality before buying.
Is St. Joseph at risk of wildfire?
Fire has reached 0% of the land around St. Joseph since 1986 (last in 2025); at low, it neither helps nor hurts the grade.
How big is the earthquake risk in St. Joseph?
Expected earthquake damage in St. Joseph comes to $0.006 a year for each $1,000 that buildings are worth.
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).