Photo: P199 · Public domainChalk River’s hazards at a glance: a moderate wildfire record and 8% of area homes over the radon guideline
The burn rate around Chalk River is 0.06% a year (1.6% of the land within 25 km since 1986), a moderate band. Earthquakes add more: NRCan’s model puts building losses at $0.11 a year per $1,000 of value, against $0.030 for the typical town. Hazard risk gives Chalk River a grade of C+; its wildfire band pulls it down.
What stands out about Chalk River’s hazards
For Chalk River, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Chalk River faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Chalk River grades C+ for hazard risk
Earthquake risk and radon make Chalk River’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #810 of 866 in Ontario and #2,002 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.
Fire reaches the land around Chalk River: 0.1% within 5 km, 1.6% within 25 km
Fires mapped since 1986 around where Chalk River’s residents live, and the fuel next to their homes.
The yearly burn rate around Chalk River is 0.06%, above 0.000% for the typical Canadian town but under the high band.
Forest thickens with distance from Chalk River: 39% of the land within 5 km, 47% 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 871
At 0.06% a year, Chalk River is near the top in Ontario: 9th of 871, behind Sioux Lookout (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.
Only 5.4% of Canada’s 2,610 towns share the moderate band with Chalk River, and 2.1% sit above it.
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 Chalk River
Flood studies whose area touches Chalk River, from NRCan’s inventory, each linked to its owner.
Nationally, Chalk River has no listed flood study; the municipality is the place to ask.
Towns with a flood study on file
69% of towns in Ontario have a flood study, more than Canada’s 58%; Chalk River is not yet one of them.
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 Chalk River’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.”
Shaking is Chalk River’s costliest hazard: $0.11 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.
Chalk River’s $0.11 is about 3.6 times the typical town’s $0.030: it sits in one of Canada’s more active seismic zones.
Shaking damage a year per $1,000 of building value
Above the middle in Ontario: Chalk River’s $0.11 against a median of $0.043, with Alexandria 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.
More earthquake risk than most: only 25% of Canada’s 2,611 towns are above Chalk River.
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 Chalk River.
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 Chalk River: 8% over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Chalk River’s area, at 8%, is close to the 6.6% of the typical Canadian town. For radon tests, the only official count covers all of the Renfrew County and District Health Unit, Chalk River included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Chalk River, 8% of tests were over 200 Bq/m³ and 1% over 600, against a median of 4% in Ontario.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
37% of Canada’s 2,611 towns share Chalk River’s band of 5 to 10%; 26% sit higher.
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.
Radon varies from house to house in Chalk River, so the survey is a reason to test, not a result for yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Chalk River
Environment and Climate Change Canada issues the weather alerts for Chalk River; 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 Chalk River, 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)
Hazards in the places around Chalk River
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Chalk River | Moderate | $0.11 | 8% | None listed |
| Deep River 4,353 · 7.7 km | Moderate | $0.099 | 8% | None listed |
The fire record around Deep River is a touch heavier than Chalk River’s, but the band is the same: moderate (here moderate).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Chalk River faces
Practical steps for Chalk River’s hazards, most pressing first.
- Clear needles and wood nearby.
- Keep a grab-and-go bag ready.
- In smoke, stay in; filter air.
- Test for three months in winter.
- Over 200 Bq/m³: fix it.
- Kits are cheap; pros test too.
- Drop, cover and hold on.
- Strap the water heater down.
- Keep 72 hours of supplies.
- Has it had a radon test?
- Ask the municipality for flood maps.
- How close is the forest edge?
- Are flood and wildfire insured?
- Is earthquake cover included?
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 Chalk River sits in.
- 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 Chalk River floods.
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Chalk River’s census subdivision (a neighbourhood shows its city’s).
- Wildfire counts one way. For Chalk River, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
Questions about flooding and hazards in Chalk River
Is radon a problem in Chalk River?
8% of the 100 homes Health Canada tested around Chalk River topped the guideline; your own house needs its own test.
Is Chalk River at risk of wildfire?
Not much by Canadian standards: Chalk River’s band is moderate, with 1.6% of the land within 25 km burned since 1986 (last in 2025), so wildfire doesn’t change its grade.
Does Chalk River flood?
No study on Canada’s Flood Map Inventory covers Chalk River (0), which doesn’t mean it has never been mapped, so ask the municipality.
How is Chalk River’s Hazard risk Grade worked out?
Chalk River grades C+ for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
How big is the earthquake risk in Chalk River?
About $0.11 a year per $1,000 of building value, NRCan’s long-run expectation for Chalk River.
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).