Photo: Óðinn · CC BY-SA 2.5 caFlood mapping exists for Centretown: 1 on record, latest by Rideau Valley Conservation Authority
Around Centretown, wildfire is practically absent from the record: 0% within 25 km since 1986, 0.001% a year. Seismic risk runs high: $0.15 of expected damage per $1,000 of buildings a year, the typical town $0.030. Centretown’s survey area, 6.2% over the radon guideline, is close to the typical town’s 6.6%. Hazard risk gives Centretown a grade of C+, from earthquakes and radon alone.
What stands out about Centretown’s hazards
Four national sources, each read for Centretown: earthquakes, radon, past fires and flood studies.
What Centretown faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Centretown grades C+ for hazard risk
Risk averages earthquakes and radon; wildfire joins only where it pulls the average down, so a town like Centretown with little fire nearby would get no credit for it.
Its place: #703 of 866 in Ontario and #1,894 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. The radon share rests on 64 home tests in the survey area, so a few homes move it. Small fires and grass fires are largely missing from the national burned-area record.
Wildfire is rare near Centretown: 0% of the land within 25 km burned since 1986, 0% within 5 km
Past fire around Centretown’s homes, from the national burned-area record, with the fuel within 5 km.
At 0.001% of the land a year, Centretown’s burn rate is in the low band; the typical Canadian town sees 0.000%.
The 5 km ring around Centretown’s homes is clear of burns since 1986, the nearest 17 km out.
The forest starts beyond town: 0.6% of the land within 5 km of Centretown’s homes is forest fuel, against 8% 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
At 0.001% a year, Centretown is near the top in Ontario: 83rd of 871, behind Sioux Lookout (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.
The low band takes in 92% of Canada’s 2,610 towns, Centretown among them, though its rate is above zero; 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.
Rideau Valley Conservation Authority has mapped flooding for Centretown (1 study)
What Canada’s Flood Map Inventory lists for Centretown: who studied flooding and where to see their maps.
Rideau Valley Conservation Authority holds the flood mapping that covers Centretown (2014), linked below.
| Study | By | Year | Status |
|---|---|---|---|
| Ottawa River | Rideau Valley Conservation Authority | 2014 | final |
Towns with a flood study on file
Centretown is one of the 69% of towns in Ontario with a flood study on file; across Canada it is 58%.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
Flood mapping is shown for Centretown to be opened and checked, never turned into a grade.
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.
Earthquakes cost buildings in Centretown $0.15 per $1,000 a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
The typical town loses $0.030 a year to shaking; Centretown loses $0.15, 5 times as much.
Shaking damage a year per $1,000 of building value
Earthquake risk in Ontario peaks in Alexandria ($0.21); Centretown, at $0.15, sits above the median of $0.043.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
15% of Canada’s 2,611 towns expect more shaking damage than Centretown, which places it in the upper third.
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 Centretown’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). · Area behind the earthquake risk figures: the city of Ottawa
Some radon around Centretown: 6.2% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
Centretown’s area sits close to the typical Canadian town: 6.2% over the guideline, against 6.6%. Centretown shares its radon tests numbers with the rest of the City of Ottawa Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon runs higher around Centretown than in most towns in Ontario: 6.2% against 4%.
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 Centretown’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 Centretown as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Centretown
Alerts for Centretown 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. |
Alert Ready carries evacuation orders for Centretown to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Centretown
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Centretown | Low | $0.15 | 6.2% | Yes |
| West Centretown 8,560 · 1.2 km | Low | $0.15 | 6.2% | Yes |
| Glebe-Dows Lake 13,436 · 1.4 km | Low | $0.15 | 6.2% | Yes |
| Old Ottawa East 8,308 · 1.6 km | Low | $0.15 | 6.2% | Yes |
| Lowertown West 5,947 · 1.9 km | Low | $0.15 | 6.2% | Yes |
| Sandy Hill 13,830 · 1.9 km | Low | $0.15 | 6.2% | Yes |
| Lowertown East 6,996 · 2.4 km | Low | $0.15 | 6.2% | Yes |
Among its neighbours Centretown has the most fire on record (low); West Centretown follows (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Centretown faces
What to do about the hazards Centretown 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
- 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 Centretown’s.
- 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 Centretown until then.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Centretown without grading them.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Centretown’s homes burned each year from 1986 to 2025, past fire rather than a forecast, and it can only lower Risk.
Questions about flooding and hazards in Centretown
Does Centretown flood?
A flood study covers Centretown on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
How big is the earthquake risk in Centretown?
In NRCan’s seismic model, Centretown’s buildings lose $0.15 per $1,000 of value in an average year.
How is Centretown’s Hazard risk Grade worked out?
Hazard risk gives Centretown C+, weighing earthquakes and radon and counting wildfire only against it.
Is Centretown at risk of wildfire?
Fire has reached 0% of the land around Centretown since 1986 (last in 2014); at low, it neither helps nor hurts the grade.
Is radon a problem in Centretown?
Around Centretown, 64 survey homes were tested and 6.2% came in over 200 Bq/m³, a guide to the area, not to any one home.
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).