Photo: FreshCorp619 · CC BY-SA 4.0Flood mapping exists for Mount Olive-Silverstone-Jamestown: 1 on record, latest by Toronto Regional Conservation Authority
Wildfire barely registers for Mount Olive-Silverstone-Jamestown, at 0% of the land within 25 km since 1986 (0.000% a year). Seismic risk in Mount Olive-Silverstone-Jamestown 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%. Mount Olive-Silverstone-Jamestown grades A− for hazard risk; wildfire is low here, so it earns no credit.
What stands out about Mount Olive-Silverstone-Jamestown’s hazards
Four national sources, each read for Mount Olive-Silverstone-Jamestown: earthquakes, radon, past fires and flood studies.
What Mount Olive-Silverstone-Jamestown faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in Mount Olive-Silverstone-Jamestown: A−
Earthquake risk and radon make Mount Olive-Silverstone-Jamestown’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: The seismic figure is a long-run average from NRCan’s model, not a prediction. 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.
Wildfire is rare near Mount Olive-Silverstone-Jamestown: 0% of the land within 25 km burned since 1986, 0% within 5 km
Fires mapped since 1986 around where Mount Olive-Silverstone-Jamestown’s residents live, and the fuel next to their homes.
With 0.000% burned a year, Mount Olive-Silverstone-Jamestown is among the many low-band places (the typical Canadian town 0.000%).
Around Mount Olive-Silverstone-Jamestown the forest is thin or far off: 0.7% of the land within 5 km and 2.1% within 25 km is forest fuel.
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
Sioux Lookout has the highest burn rate in Ontario, 0.16% a year; around Mount Olive-Silverstone-Jamestown, as around 638 of the 871 towns, it rounds to zero.
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.
Mount Olive-Silverstone-Jamestown 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.
Mount Olive-Silverstone-Jamestown is on the flood map inventory: 1 study, by Toronto Regional Conservation Authority
Flood studies whose area touches Mount Olive-Silverstone-Jamestown, from NRCan’s inventory, each linked to its owner.
For Mount Olive-Silverstone-Jamestown 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
Mount Olive-Silverstone-Jamestown 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.
Listed, not scored: a flood study proves a map exists, not that Mount Olive-Silverstone-Jamestown 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.
Earthquakes cost buildings in Mount Olive-Silverstone-Jamestown $0.043 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.
1.4 times the typical $0.030: Mount Olive-Silverstone-Jamestown’s $0.043 is ordinary.
Figures for earthquake risk are published for the city of Toronto as a whole, not for Mount Olive-Silverstone-Jamestown alone.
Shaking damage a year per $1,000 of building value
About level with the typical town in Ontario: Mount Olive-Silverstone-Jamestown’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.
Neither high nor low for Canada: 36% of the 2,611 towns expect more damage than Mount Olive-Silverstone-Jamestown.
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 Mount Olive-Silverstone-Jamestown’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).
2.7% of homes tested around Mount Olive-Silverstone-Jamestown are over the radon guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Mount Olive-Silverstone-Jamestown’s survey area reads 2.7% over the guideline, under the typical Canadian town’s 6.6%. Mount Olive-Silverstone-Jamestown doesn’t get its own radon tests figures; the ones here come from the City of Toronto Health Unit.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Against the typical town in Ontario (4%), the area around Mount Olive-Silverstone-Jamestown has fewer high tests: 2.7%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Under 5% puts Mount Olive-Silverstone-Jamestown with 37% of Canada’s 2,611 towns; 63% have more high tests.
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 survey sampled homes around Mount Olive-Silverstone-Jamestown; it can’t tell you your basement’s level.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Mount Olive-Silverstone-Jamestown
Alerts for Mount Olive-Silverstone-Jamestown 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. |
Fire danger and active fires near Mount Olive-Silverstone-Jamestown are mapped daily by the Canadian Wildland Fire Information System; evacuation orders come from the municipality or province.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Mount Olive-Silverstone-Jamestown
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Mount Olive-Silverstone-Jamestown | Low | $0.043 | 2.7% | Yes |
| Humber Summit 12,194 · 1.8 km | Low | $0.043 | 2.7% | Yes |
| Thistletown-Beaumond Heights 9,357 · 1.9 km | Low | $0.043 | 2.7% | Yes |
| West Humber-Clairville 33,690 · 2.2 km | Low | $0.043 | 2.7% | Yes |
| Rexdale-Kipling 10,378 · 3.4 km | Low | $0.043 | 2.7% | Yes |
| Humbermede 16,959 · 3.5 km | Low | $0.043 | 2.7% | Yes |
| Woodbridge 18,835 · 3.7 km | Low | $0.028 | 0% | Yes |
Fire is no heavier anywhere nearby than around Mount Olive-Silverstone-Jamestown (low), with Humber Summit next at low.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Mount Olive-Silverstone-Jamestown faces
Practical steps for Mount Olive-Silverstone-Jamestown’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
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; Mount Olive-Silverstone-Jamestown’s figure is its subdivision’s.
- Wildfire counts one way. Wildfire is read from the national burned-area record around Mount Olive-Silverstone-Jamestown’s homes since 1986, a history of fire that may lower Risk but never raises it.
- 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 Mount Olive-Silverstone-Jamestown until then.
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Mount Olive-Silverstone-Jamestown without grading them.
Questions about flooding and hazards in Mount Olive-Silverstone-Jamestown
Does Mount Olive-Silverstone-Jamestown flood?
A flood study covers Mount Olive-Silverstone-Jamestown on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
Is Mount Olive-Silverstone-Jamestown at risk of wildfire?
Hardly at all on record: 0% of the land within 25 km of Mount Olive-Silverstone-Jamestown since 1986, a low band, though small grass fires aren’t mapped.
How is Mount Olive-Silverstone-Jamestown’s Hazard risk Grade worked out?
Mount Olive-Silverstone-Jamestown grades A− for hazard risk, from earthquakes and radon, with wildfire counted only where it lowers the grade.
Is radon a problem in Mount Olive-Silverstone-Jamestown?
2.7% of the 74 homes Health Canada tested around Mount Olive-Silverstone-Jamestown topped the guideline; your own house needs its own test.
How big is the earthquake risk in Mount Olive-Silverstone-Jamestown?
About $0.043 a year per $1,000 of building value, NRCan’s long-run expectation for Mount Olive-Silverstone-Jamestown.
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).