Photo: Bio2935 · CC BY-SA 4.0Norwich is on Canada’s flood inventory: 1 listed, led by Grand River Conservation Authority
Wildfire isn’t Norwich’s worry: 0% of the land within 25 km burned since 1986 (0.000% a year). Seismic risk in Norwich sits near the middle: $0.023 of expected damage per $1,000 of buildings a year, the typical town $0.030. In Health Canada’s survey, 12% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). Hazard risk gives Norwich a grade of C+, from earthquakes and radon alone.
What stands out about Norwich’s hazards
Four national sources, each read for Norwich: earthquakes, radon, past fires and flood studies.
What Norwich faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Norwich grades C+ for hazard risk
Two inputs always count for Norwich, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #674 of 866 in Ontario and #1,793 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.
Little of the land around Norwich has burned: 0% within 5 km, 0% within 25 km since 1986
Past fire around Norwich’s homes, from the national burned-area record, with the fuel within 5 km.
The land within 25 km of Norwich burns at 0.000% a year on average, the low band; the typical Canadian town: 0.000%.
Only 0.9% of the land within 25 km of Norwich is forest fuel, and 0.6% close in.
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
Near-zero burning puts Norwich with 638 of the 871 towns in Ontario, far below Sioux Lookout 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.
Only 7.5% of Canada’s 2,610 towns are above the low band, which holds 92%; Norwich, at a rounded zero, is far from them.
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.
Norwich is on the flood map inventory: 1 study, by Grand River Conservation Authority
What Canada’s Flood Map Inventory lists for Norwich: who studied flooding and where to see their maps.
The flood study touching Norwich is Grand River Conservation Authority’s, dated 2018; its own map shows the zones street by street.
| Study | By | Year | Status |
|---|---|---|---|
| Grand River Regulatory Floodplain | Grand River Conservation Authority | 2018 | final |
Towns with a flood study on file
Mapping in Ontario reaches 69% of towns, Norwich included, beside 58% across Canada.
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 Norwich.
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.
Expected shaking damage in Norwich: $0.023 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
At $0.023 per $1,000, Norwich’s earthquake risk is about the typical Canadian town’s ($0.030; 0.8 times).
Shaking damage a year per $1,000 of building value
Norwich’s $0.023 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.
Norwich sits mid-range among Canada’s 2,611 towns: 54% 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).
Roads, pipes and bridges aren’t in Norwich’s figure, nor landslides or tsunami: it is buildings and shaking.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Radon runs high around Norwich: 12% of tested homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Measured across the Oxford County Health Unit: radon tests
A higher share than most: 12% of tested homes around Norwich, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Norwich, 12% 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.
More high tests than most: Norwich sits in a band that only 22% of Canada’s 2,611 towns share, with 4.6% 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.
The share describes the area, not a house: in Norwich as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Norwich
Environment and Climate Change Canada issues the weather alerts for Norwich; 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. |
In fire season, check CWFIS for danger and active fires around Norwich, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Norwich’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 |
|---|---|---|---|---|
| Norwich | Low | $0.023 | 12% | Yes |
| South-West Oxford 8,375 · 15 km | Low | $0.022 | 12% | None listed |
| Tillsonburg 21,450 · 16 km | Low | $0.022 | 12% | None listed |
Norwich’s low band tops its neighbours; South-West Oxford is next (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Norwich faces
What to do about the hazards Norwich 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 Norwich floods.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Norwich’s figure is its subdivision’s.
- 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 Norwich sits in.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Norwich’s homes since 1986, a history of fire that may lower Risk but never raises it.
Questions about flooding and hazards in Norwich
Is radon a problem in Norwich?
In Health Canada’s survey, 12% of 104 homes tested in Norwich’s area were above 200 Bq/m³, though only a test tells you about one house.
How big is the earthquake risk in Norwich?
In NRCan’s seismic model, Norwich’s buildings lose $0.023 per $1,000 of value in an average year.
Is Norwich at risk of wildfire?
Very little by the national record: Norwich’s band is low, with 0% of the land within 25 km burned since 1986, so wildfire doesn’t change its grade.
How is Norwich’s Hazard risk Grade worked out?
Norwich’s Hazard risk grade is C+, built on earthquakes and radon with a one-sided wildfire input.
Does Norwich flood?
Norwich’s area has been studied for flooding, and the owner’s map shows which streets lie in a zone; the grade leaves flood out.
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).