Photo: Fabian Roudra Baroi · CC BY-SA 4.0Flood mapping exists for Downsview: 1 on record, latest by Toronto Regional Conservation Authority
The national fire record shows next to nothing around Downsview, 0% of the land within 25 km since 1986 (0.000% a year). NRCan expects $0.043 of shaking damage a year per $1,000 of buildings in Downsview, near the typical $0.030. In Health Canada’s survey, just 2.7% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). Hazard risk gives Downsview a grade of A−, from earthquakes and radon alone.
What stands out about Downsview’s hazards
Four national sources, each read for Downsview: earthquakes, radon, past fires and flood studies.
What Downsview faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Downsview grades A− for hazard risk
Earthquake risk and radon make Downsview’s grade; wildfire can only lower it, never raise it, and flood studies are listed but not scored.
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. Only 74 homes were tested in the survey area, so the radon share is rough. Small fires and grass fires are largely missing from the national burned-area record.
Little of the land around Downsview has burned: 0% within 5 km, 0% within 25 km since 1986
Past fire around Downsview’s homes, from the national burned-area record, with the fuel within 5 km.
With 0.000% burned a year, Downsview is among the many low-band places (the typical Canadian town 0.000%).
Forest fuel is scarce around Downsview: 0.3% of the land within 5 km, 1.5% 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
To three decimals the burn rate around Downsview is zero, as for 638 of the 871 towns in Ontario, while Sioux Lookout reaches 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.
Measured against 2,610 towns, Downsview 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.
A flood study covers Downsview, from Toronto Regional Conservation Authority: 1 on the inventory
What Canada’s Flood Map Inventory lists for Downsview: who studied flooding and where to see their maps.
For Downsview the inventory points to Toronto Regional Conservation Authority’s 2021 study, whose map is the one to check.
| Study | By | Year | Status |
|---|---|---|---|
| Toronto Floodline Consolidation | Toronto Regional Conservation Authority | 2021 | final |
Towns with a flood study on file
Its flood study puts Downsview 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.
Listed, not scored: a flood study proves a map exists, not that Downsview floods.
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.
Ordinary seismic risk in Downsview: $0.043 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
At $0.043 per $1,000, Downsview’s earthquake risk is about the typical Canadian town’s ($0.030; 1.4 times).
Behind earthquake risk sits data gathered across the city of Toronto, with Downsview one part of it.
Shaking damage a year per $1,000 of building value
Shaking damage around Downsview runs at $0.043 a year, near the $0.043 of the typical town in Ontario; Alexandria has $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 Downsview (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).
The loss is to Downsview’s buildings alone, from ground shaking; infrastructure and secondary hazards are left out.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
2.7% of homes tested around Downsview are over the radon 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
Where the typical Canadian town has 6.6% of homes over the guideline, Downsview’s area has fewer, 2.7%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Fewer homes top the guideline around Downsview (2.7%) than in the typical town in Ontario (4%).
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
63% of Canada’s 2,611 towns have a higher share of homes over 200 Bq/m³ than Downsview’s 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.
Basements, soil and how a house is sealed decide its radon, so in Downsview only a test can say.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Downsview
Alerts for Downsview 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 Downsview 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)
Hazards in the places around Downsview
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Downsview | Low | $0.043 | 2.7% | Yes |
| Maple Leaf 10,040 · 1.7 km | Low | $0.043 | 2.7% | Yes |
| Oakdale-Beverley Heights 21,386 · 2.4 km | Low | $0.043 | 2.7% | Yes |
| Rustic 9,543 · 2.7 km | Low | $0.043 | 2.7% | Yes |
| Yorkdale-Glen Park 17,043 · 2.9 km | Low | $0.043 | 2.7% | None listed |
| York University Heights 28,557 · 3.1 km | Low | $0.043 | 2.7% | Yes |
| Glenfield-Jane Heights 30,197 · 3.1 km | Low | $0.043 | 2.7% | Yes |
None of the places around has more fire nearby than Downsview (low); Maple Leaf comes closest (low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Downsview faces
Practical steps for Downsview’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?
- Check the address on the flood map.
- Are flood and wildfire insured?
What this data can and can’t tell you
- Radon is a survey. About 14,000 homes were tested across Canada in 2009–2011, and the share over the guideline for Downsview is its health region’s, the survey’s design unit.
- Flood studies aren’t flood zones. NRCan’s inventory says where flood mapping exists, not where water goes; the map’s owner is the authority for Downsview.
- 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 Downsview’s.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Downsview’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 Downsview
Is radon a problem in Downsview?
2.7% of the 74 homes Health Canada tested around Downsview topped the guideline; your own house needs its own test.
How big is the earthquake risk in Downsview?
NRCan’s model expects shaking to cost buildings in Downsview $0.043 a year for every $1,000 of their value, on average over many years.
How is Downsview’s Hazard risk Grade worked out?
Hazard risk gives Downsview A−, weighing earthquakes and radon and counting wildfire only against it.
Is Downsview at risk of wildfire?
The burned-area record shows next to nothing around Downsview (0% within 25 km since 1986), so its band is low.
Does Downsview flood?
There is flood mapping for Downsview on the national inventory, each study linked to its owner’s map, none of them graded.
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).