Photo: Andre Carrotflower · CC BY-SA 4.0Flood mapping exists for Thunder Bay, Unorganized: 3 on record, latest by Lakehead Region Conservation Authority
Little of the land around Thunder Bay, Unorganized has burned: 1% within 25 km since 1986, or 0.03% a year. Shaking is less of a worry than in most places, at $0.004 a year per $1,000 of building value ($0.030 typical). Radon is higher than usual: 12% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Thunder Bay, Unorganized grades A− for hazard risk, with wildfire counted against it.
What stands out about Thunder Bay, Unorganized’s hazards
Four national sources, each read for Thunder Bay, Unorganized: earthquakes, radon, past fires and flood studies.
What Thunder Bay, Unorganized faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Thunder Bay, Unorganized: A−
The grade weighs Thunder Bay, Unorganized’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: #280 of 866 in Ontario and #675 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 Thunder Bay, Unorganized: 1% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Thunder Bay, Unorganized’s homes, from the national burned-area record, with the fuel within 5 km.
Around Thunder Bay, Unorganized fire takes 0.03% of the land in a typical year, the typical Canadian town 0.000%, which is low.
The closest burn since 1986 lies 6.1 km from Thunder Bay, Unorganized’s homes, none within 5 km.
Near or far, forest fuel covers a similar share around Thunder Bay, Unorganized: 80% within 5 km and 76% 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
Sioux Lookout burns fastest in Ontario at 0.16% a year; Thunder Bay, Unorganized, at 0.03%, ranks 13th of 871.
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 Thunder Bay, Unorganized 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.
Thunder Bay, Unorganized is on the flood map inventory: 3 studies, latest by Lakehead Region Conservation Authority
What Canada’s Flood Map Inventory lists for Thunder Bay, Unorganized: who studied flooding and where to see their maps.
The newest of 3 studies covering Thunder Bay, Unorganized is Lakehead Region Conservation Authority’s, from 2019; open its map to see the zones.
| Study | By | Year | Status |
|---|---|---|---|
| McVicar Creek | Lakehead Region Conservation Authority | 2019 | final · not public |
| Neebing River | Lakehead Region Conservation Authority | 2018 | final · not public |
| McIntyre River | Lakehead Region Conservation Authority | 2016 | final · not public |
Towns with a flood study on file
Its flood study puts Thunder Bay, Unorganized with 69% of towns in Ontario; Canada’s share is 58%.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Listed, not scored: a flood study proves a map exists, not that Thunder Bay, Unorganized floods.
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.
Little shaking expected in Thunder Bay, Unorganized: $0.004 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
0.1 times the typical $0.030: Thunder Bay, Unorganized’s $0.004 is low for Canada.
Shaking damage a year per $1,000 of building value
Thunder Bay, Unorganized’s $0.004 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.
Nearly every one of Canada’s 2,611 towns (98%) expects more shaking damage than Thunder Bay, Unorganized.
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 Thunder Bay, Unorganized’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).
12% of homes tested around Thunder Bay, Unorganized are over the radon guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Radon tests for the Thunder Bay District Health Unit
Radon runs above the typical Canadian town (6.6%) in Thunder Bay, Unorganized’s area, at 12%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Thunder Bay, Unorganized’s area, at 12%, is above the median in Ontario (4%), and 0.9% of its tests passed 600 Bq/m³.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
One test in ten or more tops the guideline around Thunder Bay, Unorganized, as in 22% of Canada’s 2,611 towns; 4.6% go 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.
Basements, soil and how a house is sealed decide its radon, so in Thunder Bay, Unorganized only a test can say.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Thunder Bay, Unorganized
Alerts for Thunder Bay, Unorganized come from Environment and Climate Change Canada and, for emergencies, Alert Ready.
| 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. |
Evacuation orders for Thunder Bay, Unorganized come from the municipality or the province, while CWFIS maps fire danger every day.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Get ready for what Thunder Bay, Unorganized faces
What to do about the hazards Thunder Bay, Unorganized 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 Thunder Bay, Unorganized 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 Thunder Bay, Unorganized sits in.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Thunder Bay, Unorganized’s figure is its subdivision’s.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Thunder Bay, Unorganized’s homes since 1986, a history of fire that may lower Risk but never raises it.
Questions about flooding and hazards in Thunder Bay, Unorganized
Is Thunder Bay, Unorganized at risk of wildfire?
Fire has reached 1% of the land around Thunder Bay, Unorganized since 1986 (last in 2025); at low, it neither helps nor hurts the grade.
How big is the earthquake risk in Thunder Bay, Unorganized?
In NRCan’s seismic model, Thunder Bay, Unorganized’s buildings lose $0.004 per $1,000 of value in an average year.
Does Thunder Bay, Unorganized flood?
Thunder Bay, Unorganized’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 Thunder Bay, Unorganized?
Around Thunder Bay, Unorganized, 108 survey homes were tested and 12% came in over 200 Bq/m³, a guide to the area, not to any one home.
How is Thunder Bay, Unorganized’s Hazard risk Grade worked out?
Hazard risk gives Thunder Bay, Unorganized A−, weighing earthquakes and radon and counting wildfire only against it.
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).