Photo: Bhazzard at English Wikipedia · Public domainCorunna is on Canada’s flood inventory: 1 listed, led by St. Clair Region Conservation Authority
For Corunna, wildfire history is close to nil: 0% of nearby land since 1986, 0.000% a year. Shaking is about as much of a worry in Corunna as in most places, at $0.017 a year per $1,000 of building value ($0.030 typical). About as many homes carry radon around Corunna as elsewhere, 8.4% over the guideline where the typical town has 6.6%. Hazard risk gives Corunna a grade of B+, from earthquakes and radon alone.
What stands out about Corunna’s hazards
For Corunna, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Corunna faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Corunna: B+
Earthquake risk and radon make Corunna’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #488 of 866 in Ontario and #1,090 of 2,589 Canadian towns.
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 Corunna: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Corunna’s residents live, and the fuel next to their homes.
In a typical year 0.000% of the land near Corunna burns; the typical Canadian town sees 0.000%, and both are low.
Only 1.6% of the land within 25 km of Corunna is forest fuel, and 0.2% close in.
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
Of the 871 towns in Ontario, 638 have a burn rate that rounds to zero, Corunna among them; Sioux Lookout leads at 0.16% a year.
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.
Only 7.5% of Canada’s 2,610 towns are above the low band, which holds 92%; Corunna, at a rounded zero, is far from them.
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.
A flood study covers Corunna, from St. Clair Region Conservation Authority: 1 on the inventory
Flood studies whose area touches Corunna, from NRCan’s inventory, each linked to its owner.
One study on the inventory touches Corunna, St. Clair Region Conservation Authority’s from 2009, and its area can be large, so it says a map exists, not that the town floods.
| Study | By | Year | Status |
|---|---|---|---|
| SCRCA Floodplain Estimation Study for Ontario Regulation 171-06 | St. Clair Region Conservation Authority | 2009 | final · not public |
Towns with a flood study on file
Its flood study puts Corunna with 69% of towns in Ontario; Canada’s share is 58%.
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 Corunna’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.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Ordinary seismic risk in Corunna: $0.017 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 Corunna, $0.017 per $1,000, are in line with the typical $0.030 (0.6 times).
Shaking damage a year per $1,000 of building value
Below the middle in Ontario: Corunna’s $0.017 against a median of $0.043; Alexandria has $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.
Corunna is in the lower part of Canada’s range for earthquake risk; 70% 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).
What a quake does after the shaking, fire, landslides, tsunami, falls outside NRCan’s figure for Corunna.
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 Corunna: 8.4% over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
The survey area of Corunna reads 8.4%, a shade from the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
More homes top the guideline around Corunna (8.4%) than in the typical town in Ontario (4%); 0.6% went over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Radon tops the guideline in a modest share of homes around Corunna, a band holding 37% of Canada’s 2,611 towns; 26% rank above.
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.
Health Canada advises testing every home, Corunna’s included, whatever the area’s figure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011). · Data for radon tests covers the Lambton Health Unit
Where to get warnings in Corunna
Environment and Climate Change Canada issues the weather alerts for Corunna; 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. |
For fires near Corunna, the national fire information system maps danger and active fires daily; local authorities give any evacuation order.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Corunna’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Corunna | Low | $0.017 | 8.4% | Yes |
| Point Edward 1,989 · 19 km | Low | $0.016 | 8.4% | Yes |
Nowhere around Corunna burns more: Point Edward, the closest rival, is low to its low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Corunna faces
Practical steps for Corunna’s 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?
- Check the address on the flood map.
- Are flood and wildfire insured?
What this data can and can’t tell you
- Radon is a survey. The radon share comes from about 14,000 long-term home tests in 2009–2011, pooled for now by the 2007 health region Corunna sits in.
- 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 Corunna.
- Flood studies aren’t flood zones. A study’s area can be a whole watershed or province, so being on the inventory says a map exists, not that a home in Corunna floods.
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Corunna’s included.
Questions about flooding and hazards in Corunna
How is Corunna’s Hazard risk Grade worked out?
Corunna grades B+ for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
How big is the earthquake risk in Corunna?
About $0.017 a year per $1,000 of building value, NRCan’s long-run expectation for Corunna.
Does Corunna flood?
Corunna’s area has been studied for flooding, and the owner’s map shows which streets lie in a zone; the grade leaves flood out.
Is Corunna at risk of wildfire?
No meaningful wildfire history near Corunna: 0% of nearby land since 1986, band low.
Is radon a problem in Corunna?
8.4% of the 178 homes Health Canada tested around Corunna topped the guideline; your own house needs its own test.
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).