Photo: P199 · CC BY-SA 3.0Brownsburg-Chatham’s hazards at a glance: a low wildfire record and 10% of area homes over the radon guideline
Fire seldom reaches Brownsburg-Chatham: since 1986, 0% of the land within 25 km has burned (0.001% a year). Seismic risk runs high: $0.12 of expected damage per $1,000 of buildings a year, the typical town $0.030. Brownsburg-Chatham grades C− for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Brownsburg-Chatham’s hazards
For Brownsburg-Chatham, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Brownsburg-Chatham faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Brownsburg-Chatham grades C− for hazard risk
The grade weighs Brownsburg-Chatham’s seismic risk and radon equally, and wildfire is one-sided: a high band counts against a town, a low one earns nothing.
Its place: #362 of 507 in Quebec and #2,333 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Only 78 homes were tested in the survey area, so the radon share is rough. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Few fires near Brownsburg-Chatham: 0.1% within 5 km, 0% within 25 km
Fires mapped since 1986 around where Brownsburg-Chatham’s residents live, and the fuel next to their homes.
At 0.001% of the land a year, Brownsburg-Chatham’s burn rate is in the low band; the typical Canadian town sees 0.000%.
About as much forest grows next to Brownsburg-Chatham’s homes (12% within 5 km) as across 25 km (14%).
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 Quebec · highest of 513
Brownsburg-Chatham burns at 0.001% a year, 136th of 513 towns in Quebec; the leader, Mistissini, reaches 0.31%.
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.
Low, like 92% of the country’s 2,610 towns: the land around Brownsburg-Chatham burns, but slower than in the 7.5% 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 Brownsburg-Chatham
Flood studies whose area touches Brownsburg-Chatham, from NRCan’s inventory, each linked to its owner.
Canada’s Flood Map Inventory lists no study whose area touches Brownsburg-Chatham, which doesn’t mean it has never been mapped.
Towns with a flood study on file
No study touches Brownsburg-Chatham; in Quebec, 45% of towns have one, below Canada’s 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 Brownsburg-Chatham.
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 Brownsburg-Chatham’s costliest hazard: $0.12 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 $0.12 per $1,000, Brownsburg-Chatham carries roughly 3.9 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
Typical for its province: Brownsburg-Chatham at $0.12 beside a median in Quebec of $0.14, with La Pocatière on top at $0.48.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
In the upper part of Canada’s range: 24% of its 2,611 towns expect more damage than Brownsburg-Chatham.
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).
For Brownsburg-Chatham the model prices shaking damage to buildings, nothing more.
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 Brownsburg-Chatham: 10% of area homes were over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
A higher share than most: 10% of tested homes around Brownsburg-Chatham, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon runs higher around Brownsburg-Chatham than in most towns in Quebec: 10% over the guideline (8.2% is typical), 1.3% over 600.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
4.6% of Canada’s 2,611 towns have a higher share of homes over 200 Bq/m³ than Brownsburg-Chatham, in the 10–20% band with 22%.
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, Brownsburg-Chatham’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 Laurentides health region
Where to get warnings in Brownsburg-Chatham
Environment and Climate Change Canada issues the weather alerts for Brownsburg-Chatham; 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 Brownsburg-Chatham, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Brownsburg-Chatham’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Brownsburg-Chatham | Low | $0.12 | 10% | None listed |
| Lachute 15,469 · 6.4 km | Low | $0.13 | 10% | Yes |
| Saint-André-d'Argenteuil 3,300 · 13 km | Low | $0.14 | 10% | Yes |
| Gore 2,756 · 14 km | Low | $0.097 | 10% | None listed |
| Grenville 1,889 · 15 km | Low | $0.12 | 10% | None listed |
| East Hawkesbury 3,787 · 16 km | Low | $0.20 | 6.1% | None listed |
| Hawkesbury 11,451 · 17 km | Low | $0.16 | 6.1% | Yes |
Gore burns a little more than Brownsburg-Chatham, in the same low band (low here).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Brownsburg-Chatham faces
What to do about the hazards Brownsburg-Chatham 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.
- 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.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Brownsburg-Chatham’s census subdivision (a neighbourhood shows its city’s).
- Wildfire counts one way. For Brownsburg-Chatham, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
- 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 Brownsburg-Chatham 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 Brownsburg-Chatham floods.
Questions about flooding and hazards in Brownsburg-Chatham
Is radon a problem in Brownsburg-Chatham?
In Health Canada’s survey, 10% of 78 homes tested in Brownsburg-Chatham’s area were above 200 Bq/m³, though only a test tells you about one house.
How big is the earthquake risk in Brownsburg-Chatham?
Expected earthquake damage in Brownsburg-Chatham comes to $0.12 a year for each $1,000 that buildings are worth.
Does Brownsburg-Chatham flood?
Nothing is listed for Brownsburg-Chatham on the national inventory (0); local maps may still exist with the municipality.
Is Brownsburg-Chatham at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Brownsburg-Chatham has burned since 1986, the last in 2024, a low band that leaves Risk alone.
How is Brownsburg-Chatham’s Hazard risk Grade worked out?
Brownsburg-Chatham’s Hazard risk grade is C−, built on earthquakes and radon with a one-sided wildfire input.
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).