Photo: Canmenwalker · CC BY 4.0Hazard risk in Richmond Hill is lower than in 90% of Canadian towns
Fire has left almost no mark near Richmond Hill: 0% of the land within 25 km since 1986, 0.001% a year. NRCan expects $0.028 of shaking damage a year per $1,000 of buildings in Richmond Hill, near the typical $0.030. Radon is lower than usual: 0% of tested homes in the survey area topped the guideline, against 6.6% for the typical town. Hazard risk gives Richmond Hill a grade of A; its wildfire band pulls it down.
What stands out about Richmond Hill’s hazards
For Richmond Hill, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Richmond Hill faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Richmond Hill: A
Two inputs always count for Richmond Hill, earthquakes and radon; the third, wildfire, counts only against a town.
Its place: #74 of 866 in Ontario and #383 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Wildfire is rare near Richmond Hill: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Richmond Hill’s residents live, and the fuel next to their homes.
Forty years of fire maps put Richmond Hill at 0.001% a year, low next to the typical Canadian town’s 0.000%.
The closest burn since 1986 lies 19 km from Richmond Hill’s homes, none within 5 km.
Forest fuel rises from 3.3% within 5 km of Richmond Hill to 6.2% within 25 km: the fuel lies away from 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
At 0.001% a year, Richmond Hill 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, Richmond Hill 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.
Richmond Hill is on the flood map inventory: 1 study, by Toronto Regional Conservation Authority
Flood studies whose area touches Richmond Hill, from NRCan’s inventory, each linked to its owner.
Toronto Regional Conservation Authority studied flooding in an area that includes Richmond Hill (2021); open its map to see which streets lie in a flood zone.
| Study | By | Year | Status |
|---|---|---|---|
| Toronto Floodline Consolidation | Toronto Regional Conservation Authority | 2021 | final |
Towns with a flood study on file
Mapping in Ontario reaches 69% of towns, Richmond Hill 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.
Flood studies don’t enter the grade; they are listed so you can open the official map for Richmond Hill.
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 Richmond Hill $0.028 per $1,000 a year
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
With $0.028 of shaking damage a year per $1,000, Richmond Hill is about even with the typical $0.030 (0.9 times).
Shaking damage a year per $1,000 of building value
Earthquake risk in Ontario peaks in Alexandria ($0.21); Richmond Hill, at $0.028, is below 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.
Around half of Canada’s 2,611 towns expect more shaking damage than Richmond Hill (51%).
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 Richmond Hill 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 Richmond Hill: 0% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
A lower share than most: 0% of tested homes around Richmond Hill, the typical Canadian town 6.6%. Richmond Hill shares its radon tests numbers with the rest of the York Regional Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Against the typical town in Ontario (4%), the area around Richmond Hill has fewer high tests: 0%.
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 Richmond Hill; 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.
Whatever Richmond Hill’s area share, the reading that matters is your own home’s, over a winter.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Where to get warnings in Richmond Hill
Alerts for Richmond Hill 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 Richmond Hill to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Richmond Hill’s neighbours compare on hazards
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Richmond Hill | Low | $0.028 | 0% | Yes |
| Upper Thornhill Estates 10,435 · 3.5 km | Low | $0.028 | 0% | Yes |
| The Valleys of Thornhill 9,979 · 4.4 km | Low | $0.028 | 0% | Yes |
| Cathedraltown 11,029 · 5.1 km | Low | $0.034 | 0% | Yes |
| Thornhill Woods 13,237 · 5.8 km | Low | $0.028 | 0% | Yes |
| Hope 6,997 · 5.9 km | Low | $0.028 | 0% | Yes |
| Carrville Corners 13,004 · 6.1 km | Low | $0.028 | 0% | Yes |
Fire is no heavier anywhere nearby than around Richmond Hill (low), with Cathedraltown next at low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Richmond Hill faces
What to do about the hazards Richmond Hill 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
- 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 Richmond Hill sits in.
- Wildfire counts one way. For Richmond Hill, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Richmond Hill’s census subdivision (a neighbourhood shows its city’s).
- 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 Richmond Hill floods.
Questions about flooding and hazards in Richmond Hill
Is radon a problem in Richmond Hill?
Around Richmond Hill, 95 survey homes were tested and 0% came in over 200 Bq/m³, a guide to the area, not to any one home.
Is Richmond Hill at risk of wildfire?
Fire has reached 0% of the land around Richmond Hill since 1986 (last in 2006); at low, it neither helps nor hurts the grade.
How is Richmond Hill’s Hazard risk Grade worked out?
Richmond Hill grades A for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
How big is the earthquake risk in Richmond Hill?
Expected earthquake damage in Richmond Hill comes to $0.028 a year for each $1,000 that buildings are worth.
Does Richmond Hill flood?
Richmond Hill’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).