Photo: Earth Science and Remote Sensing Unit, NASA Johnson Space Center · Public domainFlood mapping exists for Walpole Island 46: 1 on record, latest by St. Clair Region Conservation Authority
Since 1986 almost nothing has burned near Walpole Island 46: 0% of the land within 25 km, or 0.000% a year. NRCan expects $0.017 of shaking damage a year per $1,000 of buildings in Walpole Island 46, near the typical $0.030. Radon is about average around Walpole Island 46: 8.4% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Walpole Island 46 grades B+ for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Walpole Island 46’s hazards
Four national sources, each read for Walpole Island 46: earthquakes, radon, past fires and flood studies.
What Walpole Island 46 faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Walpole Island 46 grades B+ for hazard risk
For Walpole Island 46, Risk will be the average of earthquakes and radon, with wildfire added only if it makes the average worse.
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.
Few fires near Walpole Island 46: 0% within 5 km, 0% within 25 km
Fires mapped since 1986 around where Walpole Island 46’s residents live, and the fuel next to their homes.
At 0.000% of the land a year, Walpole Island 46’s burn rate is in the low band; the typical Canadian town sees 0.000%.
Forest makes up 0.7% of the land within 5 km of Walpole Island 46 and 3.6% within 25 km, little for a forest fire to run through.
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
Fire has taken almost none of the land around Walpole Island 46, as for 639 of the 872 towns in Ontario; Sioux Lookout tops the list at 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.
92% of Canada’s 2,610 towns are in the low band and 7.5% above it; Walpole Island 46 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.
St. Clair Region Conservation Authority has mapped flooding for Walpole Island 46 (1 study)
Flood studies whose area touches Walpole Island 46, from NRCan’s inventory, each linked to its owner.
A 2009 study by St. Clair Region Conservation Authority covers Walpole Island 46, and its map, not the inventory, shows the zones.
| 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 Walpole Island 46 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.
Nothing here counts toward Risk; the studies are pointers to the maps their owners keep for Walpole Island 46.
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.
Expected shaking damage in Walpole Island 46: $0.017 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 $0.017 per $1,000, Walpole Island 46’s earthquake risk is about the typical Canadian town’s ($0.030; 0.6 times).
Shaking damage a year per $1,000 of building value
At $0.017, Walpole Island 46 is below the typical town in Ontario ($0.043); Alexandria is highest at $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.
Walpole Island 46 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).
Roads, pipes and bridges aren’t in Walpole Island 46’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).
8.4% of homes tested around Walpole Island 46 are over the radon 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 Lambton Health Unit
Walpole Island 46’s area, at 8.4%, is close to the 6.6% of the typical Canadian town.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
More homes top the guideline around Walpole Island 46 (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 Walpole Island 46, 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.
A survey sample isn’t a map: any home in Walpole Island 46 can be high, and a three-month test is the only way to know.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Walpole Island 46
Environment and Climate Change Canada issues the weather alerts for Walpole Island 46; 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 Walpole Island 46, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Get ready for what Walpole Island 46 faces
Practical steps for Walpole Island 46’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
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Walpole Island 46 without grading them.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Walpole Island 46’s figure is its subdivision’s.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Walpole Island 46’s homes since 1986, a history of fire that may lower Risk but never raises it.
- 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 Walpole Island 46 until then.
Questions about flooding and hazards in Walpole Island 46
Is radon a problem in Walpole Island 46?
The area’s survey found 8.4% of 178 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Walpole Island 46.
Is Walpole Island 46 at risk of wildfire?
Very little by the national record: Walpole Island 46’s band is low, with 0% of the land within 25 km burned since 1986, so wildfire doesn’t change its grade.
How is Walpole Island 46’s Hazard risk Grade worked out?
Hazard risk gives Walpole Island 46 B+, weighing earthquakes and radon and counting wildfire only against it.
Does Walpole Island 46 flood?
A flood study covers Walpole Island 46 on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
How big is the earthquake risk in Walpole Island 46?
Expected earthquake damage in Walpole Island 46 comes to $0.017 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).