Photo: P199 · CC BY-SA 3.0A flood study covers Winchester: 3 on the national inventory, the newest from South Nation Conservation
The burned-area map is nearly blank around Winchester, 0% within 25 km since 1986, 0.000% a year. Seismic risk runs high: $0.18 of expected damage per $1,000 of buildings a year, the typical town $0.030. Winchester’s survey area, 6.1% over the radon guideline, is close to the typical town’s 6.6%. Hazard risk gives Winchester a grade of C+, from earthquakes and radon alone.
What stands out about Winchester’s hazards
Four national sources, each read for Winchester: earthquakes, radon, past fires and flood studies.
What Winchester faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Winchester grades C+ for hazard risk
Risk averages earthquakes and radon; wildfire joins only where it pulls the average down, so a town like Winchester with little fire nearby would get no credit for it.
Its place: #824 of 866 in Ontario and #2,049 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.
Few fires near Winchester: 0% within 5 km, 0% within 25 km
Past fire around Winchester’s homes, from the national burned-area record, with the fuel within 5 km.
With 0.000% burned a year, Winchester is among the many low-band places (the typical Canadian town 0.000%).
7.2% of the land within 25 km of Winchester is forest fuel, yet only 1.6% within 5 km of its homes.
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 Winchester, 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.
Measured against 2,610 towns, Winchester is in the largest group, low (92%), and at its floor, while 7.5% rank higher.
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.
3 flood studies cover Winchester, the newest from South Nation Conservation
What Canada’s Flood Map Inventory lists for Winchester: who studied flooding and where to see their maps.
South Nation Conservation and others have studied flooding in areas that include Winchester: 3 studies, the latest from 2024.
| Study | By | Year | Status |
|---|---|---|---|
| Castor River Flood Mapping | South Nation Conservation | 2024 | under review · not public |
| Flood Mapping for the South Branch of the South Nation River | South Nation Conservation | 2024 | under review · not public |
| Rideau River, Kars to Burrits Rapids | Rideau Valley Conservation Authority | 2017 | final |
Towns with a flood study on file
Flood maps are common in Ontario: 69% of towns have one, against 58% nationally, and Winchester is among them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The studies touching Winchester lean recent: 2 of 3 date from the 2020s, the first from the 2010s.
Study dates as the NRCan inventory lists them, one count per study touching Winchester.
Flood is shown here, never graded: a study says where a map exists, not how many of Winchester’s homes stand in a flood zone.
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.
High seismic risk in Winchester: $0.18 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
At $0.18 per $1,000, Winchester carries roughly 6.1 times the typical Canadian town’s earthquake risk ($0.030).
Shaking damage a year per $1,000 of building value
The typical town in Ontario expects $0.043 a year; Winchester expects $0.18, and Alexandria $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.
More earthquake risk than most: only 13% of Canada’s 2,611 towns are above Winchester.
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 Winchester’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).
Radon about average around Winchester: 6.1% over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Winchester’s area sits close to the typical Canadian town: 6.1% over the guideline, against 6.6%. Behind radon tests sits data gathered across the The Eastern Ontario Health Unit, with Winchester one part of it.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Winchester, 6.1% of tests were over 200 Bq/m³ and 1% over 600, against a median of 4% in Ontario.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
26% of Canada’s 2,611 towns have more homes over 200 Bq/m³ than Winchester’s 5–10% band, which holds 37%.
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.
The share describes the area, not a house: in Winchester as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Winchester
Environment and Climate Change Canada issues the weather alerts for Winchester; 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 Winchester, 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 Winchester’s neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Winchester | Low | $0.18 | 6.1% | Yes |
| Metcalfe 5,434 · 19 km | Low | $0.15 | 6.2% | Yes |
The neighbour with the most fire is Metcalfe (low), still no more than Winchester (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Winchester faces
What to do about the hazards Winchester 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?
- Check the address on the flood map.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- 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 Winchester until then.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Winchester without grading them.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Winchester’s figure is its subdivision’s.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Winchester’s homes since 1986, a history of fire that may lower Risk but never raises it.
Questions about flooding and hazards in Winchester
How big is the earthquake risk in Winchester?
NRCan’s model expects shaking to cost buildings in Winchester $0.18 a year for every $1,000 of their value, on average over many years.
Is Winchester at risk of wildfire?
The burned-area record shows next to nothing around Winchester (0% within 25 km since 1986), so its band is low.
How is Winchester’s Hazard risk Grade worked out?
Winchester grades C+ for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Does Winchester flood?
A flood study covers Winchester on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
Is radon a problem in Winchester?
In Health Canada’s survey, 6.1% of 99 homes tested in Winchester’s area were above 200 Bq/m³, though only a test tells you about one house.
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).