Photo: BrockvilleFact · CC BY-SA 4.0On hazards, Brockville comes out behind 90% of Canadian towns
Wildfire isn’t Brockville’s worry: 0% of the land within 25 km burned since 1986 (0.000% a year). Seismic risk runs high: $0.077 of expected damage per $1,000 of buildings a year, the typical town $0.030. Radon is higher than usual: 19% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Hazard risk gives Brockville a grade of D, from earthquakes and radon alone.
What stands out about Brockville’s hazards
Four national sources, each read for Brockville: earthquakes, radon, past fires and flood studies.
What Brockville faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Brockville grades D for hazard risk
Two inputs always count for Brockville, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #853 of 866 in Ontario and #2,477 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.
Few fires near Brockville: 0% within 5 km, 0% within 25 km
Fires mapped since 1986 around where Brockville’s residents live, and the fuel next to their homes.
The yearly burn rate around Brockville is 0.000%, low beside 0.000% for the typical Canadian town.
The forest starts beyond town: 3.9% of the land within 5 km of Brockville’s homes is forest fuel, against 12% 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
Among the 871 towns in Ontario, Sioux Lookout burns fastest (0.16% a year); Brockville is with the 638 near zero.
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.
Brockville shares the low band with 92% of Canada’s 2,610 towns, its burn rate rounding to nothing; 7.5% burn faster.
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.
Flooding around Brockville is mapped in 2 studies, the newest by Cataraqui Region Conservation Authority
Flood studies whose area touches Brockville, from NRCan’s inventory, each linked to its owner.
Cataraqui Region Conservation Authority and others have studied flooding in areas that include Brockville: 2 studies, the latest from 2024.
| Study | By | Year | Status |
|---|---|---|---|
| Cataraqui Region Conservation Authority from Kingston to Brockville | Cataraqui Region Conservation Authority | 2024 | final · not public |
| Buells and Butlers Creeks Floodplain Mapping | Cataraqui Conservation Authority | 2020 | final · not public |
Towns with a flood study on file
69% of towns in Ontario have a flood study, more than Canada’s 58%; Brockville has one too.
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 Brockville’s 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.”
Natural Resources Canada, Canada Flood Map Inventory; links go to each study’s owner.
Earthquakes cost buildings in Brockville $0.077 per $1,000 a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
The typical town loses $0.030 a year to shaking; Brockville loses $0.077, 2.6 times as much.
Shaking damage a year per $1,000 of building value
Brockville’s $0.077 tops the median in Ontario, $0.043, though Alexandria reaches $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 28% of Canada’s 2,611 towns are above Brockville.
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).
The model counts damage to Brockville’s buildings and their occupants from shaking only: not liquefaction, landslides, tsunami or fires after a quake.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Test for radon in Brockville: 19% of area homes were over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Brockville’s survey area reads 19% over the guideline, well past the typical Canadian town’s 6.6%. For radon tests, the only official count covers all of the Leeds, Grenville and Lanark District Health Unit, Brockville included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Brockville, 19% of tests were over 200 Bq/m³ and 1.9% 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.
Brockville is in the 10–20% band, with 22% of Canada’s 2,611 towns; only 4.6% are 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.
One home in Brockville can be high while next door is low; a three-month test settles it.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Brockville
Environment and Climate Change Canada issues the weather alerts for Brockville; 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 Brockville, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Brockville
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Brockville | Low | $0.077 | 19% | Yes |
| Elizabethtown-Kitley 9,886 · 11 km | Low | $0.085 | 19% | Yes |
| Augusta 7,767 · 13 km | Low | $0.11 | 19% | Yes |
| Front of Yonge 2,773 · 15 km | Low | $0.060 | 19% | Yes |
| Prescott 4,342 · 19 km | Low | $0.10 | 19% | None listed |
Nowhere around Brockville burns more: Elizabethtown-Kitley, 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 Brockville faces
What to do about the hazards Brockville 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?
- 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. 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 Brockville floods.
- 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 Brockville sits in.
- 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 Brockville’s.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Brockville’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
Questions about flooding and hazards in Brockville
Is Brockville at risk of wildfire?
Hardly at all on record: 0% of the land within 25 km of Brockville since 1986, a low band, though small grass fires aren’t mapped.
Does Brockville flood?
Brockville’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 radon a problem in Brockville?
Around Brockville, 108 survey homes were tested and 19% came in over 200 Bq/m³, a guide to the area, not to any one home.
How big is the earthquake risk in Brockville?
About $0.077 a year per $1,000 of building value, NRCan’s long-run expectation for Brockville.
How is Brockville’s Hazard risk Grade worked out?
Brockville grades D for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
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).