Photo: Community Archives · CC0Tweed’s hazards at a glance: a low wildfire record and 12% of area homes over the radon guideline
No wildfire is mapped within 25 km of Tweed’s homes since 1986 (0% of the land, 0.001% a year). NRCan expects $0.038 of shaking damage a year per $1,000 of buildings in Tweed, near the typical $0.030. Hazard risk gives Tweed a grade of C, from earthquakes and radon alone.
What stands out about Tweed’s hazards
Four national sources, each read for Tweed: earthquakes, radon, past fires and flood studies.
What Tweed faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Tweed grades C for hazard risk
The grade weighs Tweed’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: #834 of 866 in Ontario and #2,070 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. Small fires and grass fires are largely missing from the national burned-area record.
Wildfire is rare near Tweed: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Tweed’s residents live, and the fuel next to their homes.
Low: the land around Tweed burns at 0.001% a year, where the typical Canadian town sees 0.000%.
Since 1986 the nearest fire to Tweed’s homes came within 12 km, never inside 5 km.
Near or far, forest fuel covers a similar share around Tweed: 18% within 5 km and 18% 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
The land around Tweed burns at 0.001% a year, the 83rd 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.
Low, like 92% of the country’s 2,610 towns: the land around Tweed 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.
No flood study is listed for Tweed
Flood studies whose area touches Tweed, from NRCan’s inventory, each linked to its owner.
The inventory has nothing for Tweed, but a local or conservation-authority map may still exist.
Towns with a flood study on file
69% of towns in Ontario have a flood study, more than Canada’s 58%; Tweed 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 studies don’t enter the grade; they are listed so you can open the official map for Tweed.
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 Tweed: $0.038 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.
Earthquake losses in Tweed, $0.038 per $1,000, are in line with the typical $0.030 (1.3 times).
Shaking damage a year per $1,000 of building value
Shaking damage around Tweed runs at $0.038 a year, near the $0.043 of the typical town in Ontario; Alexandria has $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.
Neither high nor low for Canada: 45% of the 2,611 towns expect more damage than Tweed.
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 Tweed’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 Tweed are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · The radon tests numbers here cover the Hastings and Prince Edward Counties Health Unit
At 12% over the guideline, the area around Tweed beats the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
More homes top the guideline around Tweed (12%) than in the typical town in Ontario (4%); 2% went 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 Tweed, 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.
Basements, soil and how a house is sealed decide its radon, so in Tweed only a test can say.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Tweed
Alerts for Tweed 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 Tweed 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)
How Tweed’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Tweed | Low | $0.038 | 12% | None listed |
| Centre Hastings 5,170 · 12 km | Low | $0.034 | 12% | None listed |
| Madoc 2,467 · 14 km | Low | $0.035 | 12% | None listed |
Fire is no heavier anywhere nearby than around Tweed (low), with Centre Hastings next at low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Tweed faces
What to do about the hazards Tweed 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?
- Ask the municipality for flood maps.
- Are flood and wildfire insured?
What this data can and can’t tell you
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Tweed’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
- 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 Tweed’s.
- Flood studies aren’t flood zones. NRCan’s inventory says where flood mapping exists, not where water goes; the map’s owner is the authority for Tweed.
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Tweed is its health region’s, the survey’s design unit.
Questions about flooding and hazards in Tweed
Is radon a problem in Tweed?
In Health Canada’s survey, 12% of 99 homes tested in Tweed’s area were above 200 Bq/m³, though only a test tells you about one house.
Does Tweed flood?
Nothing is listed for Tweed on the national inventory (0); local maps may still exist with the municipality.
How is Tweed’s Hazard risk Grade worked out?
Tweed grades C for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is Tweed at risk of wildfire?
Less than most of Canada: 0% of the land within 25 km of Tweed has burned since 1986, the last in 1998, a low band that leaves Risk alone.
How big is the earthquake risk in Tweed?
About $0.038 a year per $1,000 of building value, NRCan’s long-run expectation for Tweed.
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).