Photo: Ashtabula Archive · Public domainBayham’s hazards at a glance: a low wildfire record and 7.5% of area homes over the radon guideline
No wildfire is mapped within 25 km of Bayham’s homes since 1986 (0% of the land, 0.000% a year). Seismic risk in Bayham sits near the middle: $0.022 of expected damage per $1,000 of buildings a year, the typical town $0.030. Hazard risk gives Bayham a grade of B+, from earthquakes and radon alone.
What stands out about Bayham’s hazards
Four national sources, each read for Bayham: earthquakes, radon, past fires and flood studies.
What Bayham faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Bayham: B+
Seismic risk and radon set Bayham’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #482 of 866 in Ontario and #933 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 Bayham: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Bayham’s residents live, and the fuel next to their homes.
The yearly burn rate around Bayham is 0.000%, low beside 0.000% for the typical Canadian town.
With 1.2% forest fuel within 5 km and 0.9% within 25 km, the land around Bayham gives a fire little to burn.
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 has the highest burn rate in Ontario, 0.16% a year; around Bayham, as around 638 of the 871 towns, it rounds to 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.
Bayham 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.
The flood map inventory lists nothing for Bayham
Flood studies whose area touches Bayham, from NRCan’s inventory, each linked to its owner.
Nationally, Bayham has no listed flood study; the municipality is the place to ask.
Towns with a flood study on file
Mapping in Ontario reaches 69% of towns, beside 58% across Canada, but not Bayham.
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 Bayham’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.”
Ordinary seismic risk in Bayham: $0.022 per $1,000 of buildings a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
Bayham’s $0.022 is close to the typical town’s $0.030 (0.7 times as much).
Shaking damage a year per $1,000 of building value
At $0.022, Bayham is below the typical town in Ontario ($0.043); Alexandria is highest at $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.
Bayham’s earthquake risk lands near the centre of Canada’s range; 61% of the 2,611 towns are higher.
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 Bayham’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).
7.5% of homes tested around Bayham are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Bayham’s area, at 7.5%, is close to the 6.6% of the typical Canadian town. Bayham doesn’t get its own radon tests figures; the ones here come from the Elgin-St. Thomas Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Bayham’s area, at 7.5%, is above the median in Ontario (4%), and 1.1% 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.
Radon tops the guideline in a modest share of homes around Bayham, a band holding 37% of Canada’s 2,611 towns; 26% rank above.
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.
A survey sample isn’t a map: any home in Bayham can be high, and a three-month test is the only way to know.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Bayham
Environment and Climate Change Canada issues the weather alerts for Bayham; 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 Bayham, 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)
How Bayham’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Bayham | Low | $0.022 | 7.5% | None listed |
| Malahide 9,995 · 13 km | Low | $0.022 | 7.5% | Yes |
| Aylmer 8,371 · 14 km | Low | $0.025 | 7.5% | None listed |
| Tillsonburg 21,450 · 17 km | Low | $0.022 | 12% | None listed |
The neighbour with the most fire is Malahide (low), still no more than Bayham (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Bayham faces
Practical steps for Bayham’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. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Bayham’s figure is its subdivision’s.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Bayham without grading them.
- Radon is a survey. Radon figures pool the survey’s home tests by area: postal areas once their boundaries arrive, the 2007 health region around Bayham until then.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Bayham’s homes since 1986, a history of fire that may lower Risk but never raises it.
Questions about flooding and hazards in Bayham
Is radon a problem in Bayham?
The area’s survey found 7.5% of 93 tested homes above Health Canada’s guideline, so a three-month test is worth doing in Bayham.
Is Bayham at risk of wildfire?
Hardly at all on record: 0% of the land within 25 km of Bayham since 1986, a low band, though small grass fires aren’t mapped.
How big is the earthquake risk in Bayham?
About $0.022 a year per $1,000 of building value, NRCan’s long-run expectation for Bayham.
Does Bayham flood?
The inventory has 0 studies for Bayham, and an empty list isn’t a clean bill: the municipality holds any flood maps.
How is Bayham’s Hazard risk Grade worked out?
Bayham grades B+ 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).