Photo: Boxcarphilly · CC BY 3.0Grey Highlands’ hazards at a glance: a low wildfire record and 11% of area homes over the radon guideline
Fire has left almost no mark near Grey Highlands: 0% of the land within 25 km since 1986, 0.000% a year. Earthquakes matter little: NRCan’s model puts building losses at $0.015 a year per $1,000 of value, against $0.030 for the typical town. Grey Highlands grades B for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Grey Highlands’s hazards
Four national sources, each read for Grey Highlands: earthquakes, radon, past fires and flood studies.
What Grey Highlands faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Grey Highlands grades B for hazard risk
Earthquake risk and radon make Grey Highlands’ grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #631 of 866 in Ontario and #1,460 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 Grey Highlands: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Grey Highlands’ residents live, and the fuel next to their homes.
A burn rate of 0.000% a year keeps Grey Highlands in the low band (the typical Canadian town: 0.000%).
About as much forest grows next to Grey Highlands’ homes (24% within 5 km) as across 25 km (19%).
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, Grey Highlands 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.
Most of the country’s 2,610 towns are low-band (92%, against 7.5% above); around Grey Highlands, burning 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 Grey Highlands
Flood studies whose area touches Grey Highlands, from NRCan’s inventory, each linked to its owner.
The inventory has nothing for Grey Highlands, but a local or conservation-authority map may still exist.
Towns with a flood study on file
Missing from a well-mapped province: Grey Highlands 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.
The grade leaves flood out, since a study area says nothing about how many of Grey Highlands’ homes are at risk.
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 Grey Highlands: $0.015 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.
Shaking costs the typical town $0.030 a year; in Grey Highlands it is only $0.015, 0.5 times as much.
Shaking damage a year per $1,000 of building value
Below the middle in Ontario: Grey Highlands’ $0.015 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.
72% of Canada’s 2,611 towns expect more shaking damage than Grey Highlands.
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 Grey Highlands’ 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).
11% of homes tested around Grey Highlands are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Radon tests for the Grey Bruce Health Unit
Grey Highlands’ survey area reads 11% over the guideline, well past the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
More homes top the guideline around Grey Highlands (11%) than in the typical town in Ontario (4%); 1% went over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
The 10–20% band holds 22% of Canada’s 2,611 towns, Grey Highlands among them; 4.6% 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.
The share describes the area, not a house: in Grey Highlands as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Grey Highlands
Environment and Climate Change Canada issues the weather alerts for Grey Highlands; 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 Grey Highlands, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Grey Highlands’ neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Grey Highlands | Low | $0.015 | 11% | None listed |
| Dundalk 11,599 · 18 km | Low | $0.017 | 11% | Yes |
The neighbour with the most fire is Dundalk (low), still no more than Grey Highlands (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Grey Highlands faces
Practical steps for Grey Highlands’ 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
- 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 Grey Highlands floods.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Grey Highlands’ homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- 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 Grey Highlands’.
- 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 Grey Highlands sits in.
Questions about flooding and hazards in Grey Highlands
Does Grey Highlands flood?
The inventory has 0 studies for Grey Highlands, and an empty list isn’t a clean bill: the municipality holds any flood maps.
Is radon a problem in Grey Highlands?
The area’s survey found 11% of 98 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Grey Highlands.
How is Grey Highlands’s Hazard risk Grade worked out?
Grey Highlands’ Hazard risk grade is B, built on earthquakes and radon with a one-sided wildfire input.
How big is the earthquake risk in Grey Highlands?
About $0.015 a year per $1,000 of building value, NRCan’s long-run expectation for Grey Highlands.
Is Grey Highlands at risk of wildfire?
The burned-area record shows next to nothing around Grey Highlands (0% within 25 km since 1986), so its band is low.
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).