Photo: SimonP · CC BY-SA 3.0Princess-Rosethorn is on Canada’s flood inventory: 1 listed, led by Toronto Regional Conservation Authority
Since 1986 almost nothing has burned near Princess-Rosethorn: 0% of the land within 25 km, or 0.000% a year. Seismic risk in Princess-Rosethorn sits near the middle: $0.043 of expected damage per $1,000 of buildings a year, the typical town $0.030. Fewer homes than usual carry radon here, 2.7% over the guideline where the typical town has 6.6%. Hazard risk gives Princess-Rosethorn a grade of A−, from earthquakes and radon alone.
What stands out about Princess-Rosethorn’s hazards
For Princess-Rosethorn, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Princess-Rosethorn faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Princess-Rosethorn: A−
Risk averages earthquakes and radon; wildfire joins only where it pulls the average down, so a town like Princess-Rosethorn with little fire nearby would get no credit for it.
Its place: #285 of 866 in Ontario and #700 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The radon share rests on 74 home tests in the survey area, so a few homes move it. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Little of the land around Princess-Rosethorn has burned: 0% within 5 km, 0% within 25 km since 1986
Past fire around Princess-Rosethorn’s homes, from the national burned-area record, with the fuel within 5 km.
In a typical year 0.000% of the land near Princess-Rosethorn burns; the typical Canadian town sees 0.000%, and both are low.
Forest fuel is scarce around Princess-Rosethorn: 0.5% of the land within 5 km, 0.8% 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
Of the 871 towns in Ontario, 638 have a burn rate that rounds to zero, Princess-Rosethorn among them; Sioux Lookout leads at 0.16% a year.
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.
Princess-Rosethorn 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.
Princess-Rosethorn is on the flood map inventory: 1 study, by Toronto Regional Conservation Authority
What Canada’s Flood Map Inventory lists for Princess-Rosethorn: who studied flooding and where to see their maps.
Toronto Regional Conservation Authority holds the flood mapping that covers Princess-Rosethorn (2021), linked below.
| Study | By | Year | Status |
|---|---|---|---|
| Toronto Floodline Consolidation | Toronto Regional Conservation Authority | 2021 | final |
Towns with a flood study on file
Its flood study puts Princess-Rosethorn with 69% of towns in Ontario; Canada’s share 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 Princess-Rosethorn 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.
Expected shaking damage in Princess-Rosethorn: $0.043 a year per $1,000
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Princess-Rosethorn’s $0.043 is close to the typical town’s $0.030 (1.4 times as much).
For earthquake risk, the only official count covers all of the city of Toronto, Princess-Rosethorn included.
Shaking damage a year per $1,000 of building value
About level with the typical town in Ontario: Princess-Rosethorn’s $0.043 against $0.043; Alexandria reaches $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.
Around half of Canada’s 2,611 towns expect more shaking damage than Princess-Rosethorn (36%).
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).
For Princess-Rosethorn the model prices shaking damage to buildings, nothing more.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Little radon around Princess-Rosethorn: 2.7% of area homes over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline. · Measured across the City of Toronto Health Unit: radon tests
At 2.7% over the guideline, the area around Princess-Rosethorn is under the typical Canadian town’s 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon runs lower around Princess-Rosethorn than in most towns in Ontario: 2.7% against 4%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
The quietest radon band, under 5%, holds 37% of Canada’s 2,611 towns and Princess-Rosethorn; 63% sit higher.
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.
Neighbouring homes in Princess-Rosethorn can differ a lot; only a long-term test tells you about yours.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Princess-Rosethorn
Alerts for Princess-Rosethorn 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 Princess-Rosethorn 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 Princess-Rosethorn’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 |
|---|---|---|---|---|
| Princess-Rosethorn | Low | $0.043 | 2.7% | Yes |
| Edenbridge-Humber Valley 15,480 · 1.9 km | Low | $0.043 | 2.7% | Yes |
| Willowridge-Martingrove-Richview 22,456 · 2.1 km | Low | $0.043 | 2.7% | Yes |
| Islington 23,659 · 2.3 km | Low | $0.043 | 2.7% | Yes |
| Eringate-Centennial-West Deane 18,501 · 2.8 km | Low | $0.043 | 2.7% | Yes |
| Etobicoke West Mall 12,218 · 2.9 km | Low | $0.043 | 2.7% | Yes |
| Kingsway South 8,935 · 3.0 km | Low | $0.043 | 2.7% | Yes |
Among its neighbours Princess-Rosethorn has the most fire on record (low); Edenbridge-Humber Valley follows (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Princess-Rosethorn faces
What to do about the hazards Princess-Rosethorn 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
- Earthquakes are modelled. The earthquake figure is an expected loss, not a forecast, worked out by NRCan for each census subdivision, Princess-Rosethorn’s included.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Princess-Rosethorn takes its 2007 health region’s share.
- Flood studies aren’t flood zones. The flood inventory points to maps; it is incomplete and not the official source, so ask the municipality about any street in Princess-Rosethorn.
- Wildfire counts one way. Burned land within 25 km of where people live, averaged over 1986–2025 and checked for fuel near homes, is the measure; it looks back, not ahead, and only ever counts against Princess-Rosethorn.
Questions about flooding and hazards in Princess-Rosethorn
How is Princess-Rosethorn’s Hazard risk Grade worked out?
Princess-Rosethorn’s Hazard risk grade is A−, built on earthquakes and radon with a one-sided wildfire input.
Does Princess-Rosethorn flood?
The inventory lists a study touching Princess-Rosethorn; whether a given street floods is on that map, not in the grade.
Is radon a problem in Princess-Rosethorn?
Around Princess-Rosethorn, 74 survey homes were tested and 2.7% came in over 200 Bq/m³, a guide to the area, not to any one home.
Is Princess-Rosethorn at risk of wildfire?
No meaningful wildfire history near Princess-Rosethorn: 0% of nearby land since 1986, band low.
How big is the earthquake risk in Princess-Rosethorn?
In NRCan’s seismic model, Princess-Rosethorn’s buildings lose $0.043 per $1,000 of value in an average year.
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).