Photo: Martin Cathrae from Charlottetown, PE, Canada · CC BY-SA 2.0Merrickville faces more hazards than 93% of Canadian towns
For Merrickville, wildfire history is close to nil: 0% of nearby land since 1986, 0.000% a year. Shaking is a bigger worry than in most places, at $0.10 a year per $1,000 of building value ($0.030 typical). More homes than usual carry radon here, 19% over the guideline where the typical town has 6.6%. Hazard risk gives Merrickville a grade of D, from earthquakes and radon alone.
What stands out about Merrickville’s hazards
Four national sources, each read for Merrickville: earthquakes, radon, past fires and flood studies.
What Merrickville faces
Each hazard against its own yardstick; meters run from low to high on that yardstick.
Wildfire
Earthquakes
Radon
Flood study
Merrickville grades D for hazard risk
Seismic risk and radon set Merrickville’s grade, wildfire can drag it down, and flood mapping stays out of it.
Its place: #858 of 866 in Ontario and #2,500 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 Merrickville has burned: 0% within 5 km, 0% within 25 km since 1986
Past fire around Merrickville’s homes, from the national burned-area record, with the fuel within 5 km.
At 0.000% of the land a year, Merrickville’s burn rate is in the low band; the typical Canadian town sees 0.000%.
Forest fuel is spread evenly around Merrickville: 19% within 5 km, 15% 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
Fire has taken almost none of the land around Merrickville, as for 638 of the 871 towns in Ontario; Sioux Lookout tops the list at 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 holds 92% of Canada’s 2,610 towns, and Merrickville sits at its very bottom; only 7.5% are above it.
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.
Flooding around Merrickville is mapped in 7 studies, the newest by Rideau Valley Conservation Authority
What Canada’s Flood Map Inventory lists for Merrickville: who studied flooding and where to see their maps.
For Merrickville the inventory points to 7 studies, most recently Rideau Valley Conservation Authority’s in 2017.
| Study | By | Year | Status |
|---|---|---|---|
| Rideau River, Kars to Burrits Rapids | Rideau Valley Conservation Authority | 2017 | final |
| Otter and Hutton Creeks | Rideau Valley Conservation Authority | 2016 | final |
| Rideau River, Poonamalie Dam to Smith Falls | Rideau Valley Conservation Authority | 2010 | final |
| Kemptville Creek | Rideau Valley Conservation Authority | 2009 | final |
| Rideau River Tributaries, Smiths Falls to Kars | Rideau Valley Conservation Authority | 1983 | final |
| Rideau River Floodline Mapping, Smiths Falls to Poonamalie | Rideau Valley Conservation Authority | 1979 | final |
| Rideau River, Smiths Falls to Kars | Rideau Valley Conservation Authority | 1976 | final |
Towns with a flood study on file
Merrickville 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.
The studies touching Merrickville lean recent: 3 of 7 date from the 2010s, the first from the 1970s.
Study dates as the NRCan inventory lists them, one count per study touching Merrickville.
The grade leaves flood out, since a study area says nothing about how many of Merrickville’s homes are at risk.
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.
High seismic risk in Merrickville: $0.10 per $1,000 of buildings a year
Expected yearly building losses from earthquakes, from Natural Resources Canada’s model.
Merrickville’s $0.10 is about 3.4 times the typical town’s $0.030: it sits in one of Canada’s more active seismic zones.
Shaking damage a year per $1,000 of building value
Earthquake risk in Ontario peaks in Alexandria ($0.21); Merrickville, at $0.10, sits above 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.
More earthquake risk than most: only 25% of Canada’s 2,611 towns are above Merrickville.
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 model counts damage to Merrickville’s buildings and their occupants from shaking only: not liquefaction, landslides, tsunami or fires after a quake.
Natural Resources Canada, Canada’s Seismic Risk Model (2022), by census subdivision (2016 boundaries; a few 2021 subdivisions take their residents’ mean).
Test for radon in Merrickville: 19% of area homes were over the guideline
Long-term radon tests in homes across the survey area, against Health Canada’s guideline.
At 19% over the guideline, the area around Merrickville beats the typical Canadian town’s 6.6%. For radon tests, the only official count covers all of the Leeds, Grenville and Lanark District Health Unit, Merrickville included.
Tested homes over 200 Bq/m³
Over 600 Bq/m³
Around Merrickville, 19% of tests were over 200 Bq/m³ and 1.9% over 600, against a median of 4% in Ontario.
Health Canada radon survey (2009–2011), by 2007 health region; medians of towns of 2,500 people or more.
More high tests than most: Merrickville sits in a band that only 22% of Canada’s 2,611 towns share, with 4.6% above.
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 Merrickville as anywhere, test to be sure.
Health Canada, Cross-Canada Survey of Radon Concentrations in Homes (2009–2011).
Weather and fire alerts for Merrickville
Environment and Climate Change Canada issues the weather alerts for Merrickville; 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. |
In fire season, check CWFIS for danger and active fires around Merrickville, and listen to local authorities for orders.
Weather alerts (ECCC) · Alert Ready · Fire danger and active fires (CWFIS)
How Merrickville’s neighbours compare on hazards
Wildfire band, earthquake risk, radon and flood studies for each place nearby.
| Town | Wildfire | Quake $/1,000 | Radon | Flood study |
|---|---|---|---|---|
| Merrickville | Low | $0.10 | 19% | Yes |
| Montague 4,414 · 12 km | Low | $0.10 | 19% | Yes |
| Smiths Falls 11,093 · 12 km | Low | $0.092 | 19% | Yes |
Montague (low) has the heaviest fire record of Merrickville’s neighbours, and Merrickville (low) matches or beats it.
Radon is the survey area’s figure, so neighbours in one area share it.
Get ready for what Merrickville faces
Practical steps for Merrickville’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.
- 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
- Flood studies aren’t flood zones. Flood studies cover areas of every size, which is why the page lists them for Merrickville without grading them.
- 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 Merrickville’s.
- 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 Merrickville until then.
- Wildfire counts one way. The wildfire figure is the share of land within 25 km of Merrickville’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 Merrickville
Does Merrickville flood?
A flood study covers Merrickville on Canada’s Flood Map Inventory; open the owner’s map to check a street, since flood isn’t graded.
How is Merrickville’s Hazard risk Grade worked out?
Hazard risk gives Merrickville D, weighing earthquakes and radon and counting wildfire only against it.
Is radon a problem in Merrickville?
19% of the 108 homes Health Canada tested around Merrickville topped the guideline; your own house needs its own test.
Is Merrickville at risk of wildfire?
No meaningful wildfire history near Merrickville: 0% of nearby land since 1986, band low.
How big is the earthquake risk in Merrickville?
NRCan’s model expects shaking to cost buildings in Merrickville $0.10 a year for every $1,000 of their value, on average over many years.
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).