Photo: Gerry Thomasen from Nanaimo, Canada · CC BY 2.0Earthquakes are Nanaimo’s biggest hazard: $0.59 of damage a year per $1,000 of buildings, 20 times the norm
Little of the land around Nanaimo has burned: 0.2% within 25 km since 1986, or 0.005% a year. In Health Canada’s survey, just 0.9% of homes tested in the area exceeded 200 Bq/m³ (6.6% typical). Hazard risk gives Nanaimo a grade of B−; its wildfire band pulls it down.
What stands out about Nanaimo’s hazards
For Nanaimo, from NRCan’s seismic model, Health Canada’s radon survey, the national burned-area record and the flood map inventory.
What Nanaimo faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Nanaimo grades B− for hazard risk
Risk averages earthquakes and radon; wildfire joins only where it pulls the average down, so a town like Nanaimo with little fire nearby would get no credit for it.
Its place: #130 of 254 in British Columbia and #1,649 of 2,589 Canadian towns.
How sure: Earthquake losses are a model’s expectation over many years, not a forecast for any one. The burned-area record misses fires under about 10 ha and most grass and farm fires.
Little of the land around Nanaimo has burned: 0% within 5 km, 0.2% within 25 km since 1986
Fires mapped since 1986 around where Nanaimo’s residents live, and the fuel next to their homes.
Forty years of fire maps put Nanaimo at 0.005% a year, low next to the typical Canadian town’s 0.000%.
Forest fuel covers 45% of the land close to Nanaimo and 68% across 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 British Columbia · highest of 255
At 0.005% a year, Nanaimo ranks 121st of the 255 towns in British Columbia; Oliver leads at 0.98%.
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.
7.5% of Canada’s 2,610 towns burn fast enough to rank moderate or above; Nanaimo stays low, with 92%.
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.
Nanaimo is on the flood map inventory: 1 study, by Ministry of Environment and Climate Change Strategy
Flood studies whose area touches Nanaimo, from NRCan’s inventory, each linked to its owner.
Ministry of Environment and Climate Change Strategy studied flooding in an area that includes Nanaimo (1984); open its map to see which streets lie in a flood zone.
| Study | By | Year | Status |
|---|---|---|---|
| Nanaimo River Floodplain Mapping (including Haslam Creek) | Ministry of Environment and Climate Change Strategy | 1984 | final |
Towns with a flood study on file
Its flood study puts Nanaimo with 76% of towns in British Columbia; 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 studies don’t enter the grade; they are listed so you can open the official map for Nanaimo.
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.
Shaking is Nanaimo’s costliest hazard: $0.59 a year per $1,000
NRCan’s seismic risk model: the damage shaking is expected to do to buildings each year, on average over many years.
The typical town loses $0.030 a year to shaking; Nanaimo loses $0.59, 19.7 times as much.
Shaking damage a year per $1,000 of building value
At $0.59, Nanaimo is above the typical town in British Columbia ($0.36); Duncan has the most at $1.33.
NRCan seismic risk model (2022): mean yearly building loss per $1,000 of value; medians of towns of 2,500 people or more.
Few of Canada’s 2,611 towns face more earthquake damage than Nanaimo: 0.9% of them.
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).
What a quake does after the shaking, fire, landslides, tsunami, falls outside NRCan’s figure for Nanaimo.
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 Nanaimo: 0.9% of area homes over the guideline
Health Canada’s survey of long-term home tests: the share above the 200 Bq/m³ guideline.
Radon runs below the typical Canadian town (6.6%) in Nanaimo’s area, at 0.9%. Behind radon tests sits data gathered across the Central Vancouver Island health region, with Nanaimo one part of it.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
The median in British Columbia is 1.8% over 200 Bq/m³; around Nanaimo it is 0.9%.
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 Nanaimo, 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.
Whatever Nanaimo’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 Nanaimo
Alerts for Nanaimo 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 Nanaimo to phones; CWFIS shows the day’s fire danger.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
Hazards in the places around Nanaimo
The same four hazards for the places next door.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Nanaimo | Low | $0.59 | 0.9% | Yes |
| Electoral Area C, Nanaimo 3,733 · 3.4 km | Low | $0.44 | 0.9% | Yes |
| Lantzville 4,276 · 9.9 km | Low | $0.50 | 0.9% | None listed |
| Electoral Area A, Nanaimo 7,825 · 14 km | Low | $0.54 | 0.9% | Yes |
| Electoral Area B, Nanaimo 4,702 · 14 km | Low | $0.39 | 0.9% | None listed |
| Fairwinds 7,125 · 17 km | Low | $0.34 | 0.9% | None listed |
Electoral Area B, Nanaimo burns a little more than Nanaimo, in the same low band (low here).
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Nanaimo faces
What to do about the hazards Nanaimo 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.
- Drop, cover and hold on.
- Strap the water heater down.
- Keep 72 hours of supplies.
- Has it had a radon test?
- Check the address on the flood map.
- Are flood and wildfire insured?
- Is earthquake cover included?
What this data can and can’t tell you
- Earthquakes are modelled. Seismic risk is NRCan’s model of yearly building losses from shaking, averaged over many years and given for Nanaimo’s census subdivision (a neighbourhood shows its city’s).
- 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 Nanaimo.
- Radon is a survey. Health Canada’s survey tested some 14,000 homes over three months; until postal-area boundaries are loaded, Nanaimo takes its 2007 health region’s share.
- Wildfire counts one way. For Nanaimo, wildfire means how much nearby land burned in the past forty years, a one-way input that can pull Risk down and nothing more.
Questions about flooding and hazards in Nanaimo
Is Nanaimo at risk of wildfire?
Fire has reached 0.2% of the land around Nanaimo since 1986 (last in 2025); at low, it neither helps nor hurts the grade.
Is radon a problem in Nanaimo?
Around Nanaimo, 109 survey homes were tested and 0.9% came in over 200 Bq/m³, a guide to the area, not to any one home.
Does Nanaimo flood?
The inventory lists a study touching Nanaimo; whether a given street floods is on that map, not in the grade.
How big is the earthquake risk in Nanaimo?
About $0.59 a year per $1,000 of building value, NRCan’s long-run expectation for Nanaimo.
How is Nanaimo’s Hazard risk Grade worked out?
Nanaimo’s Hazard risk grade is B−, built on earthquakes and radon with a one-sided wildfire input.
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).