Photo: Quintin Soloviev · CC BY 4.0Hazard risk in St. John's is lower than in 93% of Canadian towns
Burn scars are few around St. John's, with 0.7% of the land within 25 km touched by fire since 1986 (0.02% a year). Seismic risk runs low: $0.011 of expected damage per $1,000 of buildings a year, the typical town $0.030. In Health Canada’s survey, just 4% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). St. John's grades A for hazard risk, with wildfire counted against it.
What stands out about St. John's’s hazards
Four national sources, each read for St. John's: earthquakes, radon, past fires and flood studies.
What St. John's faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Hazard risk in St. John's: A
The grade weighs St. John's’ seismic risk and radon equally, and wildfire is one-sided: a high band counts against a town, a low one earns nothing.
Its place: #11 of 32 in Newfoundland and Labrador and #278 of 2,589 Canadian towns.
How sure: The seismic figure is a long-run average from NRCan’s model, not a prediction. Small fires and grass fires are largely missing from the national burned-area record.
Little of the land around St. John's has burned: 1.2% within 5 km, 0.7% within 25 km since 1986
Fires mapped since 1986 around where St. John's’ residents live, and the fuel next to their homes.
The land within 25 km of St. John's burns at 0.02% a year on average, the low band; the typical Canadian town: 0.000%.
Forest thickens with distance from St. John's: 58% of the land within 5 km, 65% 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 Newfoundland and Labrador · highest of 32
Labrador City tops the 32 towns in Newfoundland and Labrador at 0.43% a year; St. John's, at 0.02%, comes 17th.
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.
Beside 2,610 Canadian towns, St. John's reads low, with 92% of them; only 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.
St. John's is on the flood map inventory: 5 studies, latest by GNL Department of Environment, Conservation and Climate Change
Flood studies whose area touches St. John's, from NRCan’s inventory, each linked to its owner.
GNL Department of Environment, Conservation and Climate Change and others have studied flooding in areas that include St. John's: 5 studies, the latest from 2025.
| Study | By | Year | Status |
|---|---|---|---|
| City of St. John's Flood Mapping Study | GNL Department of Environment, Conservation and Climate Change | 2025 | final |
| Waterford River Area | Department of Environment and Climate Change | 2018 | final |
| Portugal Cove - St Philips | Department of Environment and Climate Change | 2015 | final |
| Goulds-Petty Harbour Area | Department of Environment and Climate Change | 2013 | final |
| Logy Bay - Middle Cove - Outer Cove | Department of Environment and Climate Change | 2012 | final |
Towns with a flood study on file
Flood maps are common in Newfoundland and Labrador: 59% of towns have one, against 58% nationally, and St. John's is among them.
NRCan Canada Flood Map Inventory: a study footprint touching the town’s boundary; towns of 2,500 people or more.
The busiest decade for flood studies around St. John's was the 2010s (4 of 5); they run from the 2010s to the 2020s.
Study dates as the NRCan inventory lists them, one count per study touching St. John's.
Flood is shown here, never graded: a study says where a map exists, not how many of St. John's’ homes stand in a flood zone.
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 St. John's just $0.011 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.
St. John's’ $0.011 is a fraction of the typical town’s $0.030 (0.4 times as much): quiet ground by Canadian standards.
Shaking damage a year per $1,000 of building value
The median in Newfoundland and Labrador is $0.011; St. John's, at $0.011, is right beside it, and Holyrood tops the list at $0.015.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
85% of Canada’s 2,611 towns expect more shaking damage than St. John's.
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 St. John'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).
Little radon around St. John's: 4% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline. · Area-wide: radon tests, counted over the Eastern Regional Integrated Health Authority
A lower share than most: 4% of tested homes around St. John's, the typical Canadian town 6.6%.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Radon around St. John's is ordinary for towns in Newfoundland and Labrador: 4%, beside a median of 4%.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
Radon rarely tops the guideline around St. John's, as for 37% of Canada’s 2,611 towns; 63% see more.
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 St. John's as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for St. John's
Environment and Climate Change Canada issues the weather alerts for St. John's; Alert Ready carries the urgent ones to phones, radio and TV.
| 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. |
Smoke and fire warnings for St. John's come through Environment Canada and Alert Ready; the fire map is CWFIS’s.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around St. John's
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| St. John's | Low | $0.011 | 4% | Yes |
| Mount Pearl 24,266 · 6.6 km | Low | $0.011 | 4% | Yes |
| Petty Harbour-Maddox Cove 1,005 · 9.4 km | Low | $0.012 | 4% | Yes |
| Portugal Cove-St. Philip's 9,167 · 9.7 km | Low | $0.013 | 4% | Yes |
| Paradise 26,155 · 9.8 km | Low | $0.015 | 4% | Yes |
| Logy Bay-Middle Cove-Outer Cove 2,601 · 10 km | Low | $0.013 | 4% | Yes |
| Torbay 8,297 · 11 km | Low | $0.011 | 4% | Yes |
The fire record around Logy Bay-Middle Cove-Outer Cove is a touch heavier than St. John's’, but the band is the same: low (here low).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what St. John's faces
What to do about the hazards St. John's 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 St. John's sits in.
- Wildfire counts one way. Wildfire is read from the national burned-area record around St. John's’ homes since 1986, a history of fire that may lower Risk but never raises it.
- 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 St. John's floods.
- Earthquakes are modelled. NRCan models what earthquakes would cost buildings each year on average, subdivision by subdivision; St. John's’ figure is its subdivision’s.
Questions about flooding and hazards in St. John's
How big is the earthquake risk in St. John's?
About $0.011 a year per $1,000 of building value, NRCan’s long-run expectation for St. John's.
How is St. John's’s Hazard risk Grade worked out?
Hazard risk gives St. John's A, weighing earthquakes and radon and counting wildfire only against it.
Is radon a problem in St. John's?
In Health Canada’s survey, 4% of 100 homes tested in St. John's’ area were above 200 Bq/m³, though only a test tells you about one house.
Is St. John's at risk of wildfire?
Less than most of Canada: 0.7% of the land within 25 km of St. John's has burned since 1986, the last in 2025, a low band that leaves Risk alone.
Does St. John's flood?
St. John'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).