Photo: Quintin Soloviev · CC BY 4.0Black River-Matheson faces fewer hazards than 85% of Canadian towns
Little of the land around Black River-Matheson has burned: 0.1% within 25 km since 1986, or 0.003% a year. Seismic risk in Black River-Matheson sits near the middle: $0.033 of expected damage per $1,000 of buildings a year, the typical town $0.030. In Health Canada’s survey, just 1% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). Black River-Matheson grades A for hazard risk, with wildfire counted against it.
What stands out about Black River-Matheson’s hazards
For Black River-Matheson, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Black River-Matheson faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Black River-Matheson grades A for hazard risk
Earthquake risk and radon make Black River-Matheson’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
Its place: #227 of 866 in Ontario and #567 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.
Wildfire is rare near Black River-Matheson: 0.1% of the land within 25 km burned since 1986, 0.4% within 5 km
Past fire around Black River-Matheson’s homes, from the national burned-area record, with the fuel within 5 km.
At 0.003% of the land a year, Black River-Matheson’s burn rate is in the low band; the typical Canadian town sees 0.000%.
The nearer ring around Black River-Matheson is less wooded (36% forest fuel) than the land out to 25 km (57%).
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
The land around Black River-Matheson burns at 0.003% a year, the 50th highest rate of 871 towns in Ontario; Sioux Lookout tops it 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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Black River-Matheson stays low, with 92%.
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 Black River-Matheson
What Canada’s Flood Map Inventory lists for Black River-Matheson: who studied flooding and where to see their maps.
There is no study for Black River-Matheson on the national flood inventory, which is far from complete.
Towns with a flood study on file
Flood maps are common in Ontario, 69% of towns against 58% nationally, but none in the inventory touches Black River-Matheson.
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 Black River-Matheson.
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.”
Expected shaking damage in Black River-Matheson: $0.033 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
1.1 times the typical $0.030: Black River-Matheson’s $0.033 is ordinary.
Shaking damage a year per $1,000 of building value
Black River-Matheson’s $0.033 sits under the median in Ontario, $0.043, and well under Alexandria’s $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.
Black River-Matheson sits mid-range among Canada’s 2,611 towns: 48% expect more shaking damage.
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 Black River-Matheson.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Little radon around Black River-Matheson: 1% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Black River-Matheson’s survey area reads 1% over the guideline, under the typical Canadian town’s 6.6%. Black River-Matheson doesn’t get its own radon tests figures; the ones here come from the Porcupine Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Against the typical town in Ontario (4%), the area around Black River-Matheson has fewer high tests: 1%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Under 5% puts Black River-Matheson with 37% of Canada’s 2,611 towns; 63% have more high tests.
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 Black River-Matheson, 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 Black River-Matheson
Environment and Climate Change Canada issues the weather alerts for Black River-Matheson; 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 Black River-Matheson, 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)
Get ready for what Black River-Matheson faces
Practical steps for Black River-Matheson’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?
- Ask the municipality for flood maps.
- Are flood and wildfire insured?
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 Black River-Matheson’s census subdivision (a neighbourhood shows its city’s).
- Wildfire counts one way. For Black River-Matheson, 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 Black River-Matheson 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 Black River-Matheson floods.
Questions about flooding and hazards in Black River-Matheson
Is radon a problem in Black River-Matheson?
1% of the 96 homes Health Canada tested around Black River-Matheson topped the guideline; your own house needs its own test.
How big is the earthquake risk in Black River-Matheson?
In NRCan’s seismic model, Black River-Matheson’s buildings lose $0.033 per $1,000 of value in an average year.
How is Black River-Matheson’s Hazard risk Grade worked out?
Black River-Matheson grades A for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Does Black River-Matheson flood?
No study on Canada’s Flood Map Inventory covers Black River-Matheson (0), which doesn’t mean it has never been mapped, so ask the municipality.
Is Black River-Matheson at risk of wildfire?
Not much by Canadian standards: Black River-Matheson’s band is low, with 0.1% of the land within 25 km burned since 1986 (last in 2018), so wildfire doesn’t change its 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).