January 19, 2026 - Bergeron Clifford LLP

Significant Weather Events (SWE) and Winter Accident Lawsuits in Ottawa and Pembroke

During winter storms in Ottawa, Pembroke and Southern Ontario, slip and fall accidents and car crashes increase dramatically.

Roads and sidewalks become snowier and icier. Hazards abound. Plows and crews are that much busier – and it takes them that much longer to address all the roads and sidewalks.

To protect themselves from liability, municipalities will typically declare a “significant weather event” when winter storms strike. Under Ontario’s Minimum Maintenance Standards for Municipal Highways (MMS), declaring a significant weather event lowers the standard required of a municipality to address ice and snow accumulation.

If you’ve been injured in a slip and fall or car accident during a winter storm in Eastern Ontario, you may wonder how a municipality’s declaration of a “Significant Weather Event” (SWE) affects your right to sue. Understanding these rules is crucial for anyone pursuing a personal injury claim against a city or town after a snow or ice-related accident.

What Is a Significant Weather Event (SWE) in Ontario?

An SWE is typically declared when Environment Canada issues alerts for severe weather, such as heavy snow, freezing rain, or ice storms. During an SWE, the usual timelines for clearing snow and treating ice on roads, sidewalks, and bike lanes are temporarily suspended. This means the municipality’s legal obligations to maintain safe conditions are altered until the SWE ends (O. Reg. 239/02: MINIMUM MAINTENANCE STANDARDS …).

How Significant Weather Events Affect Liability for Winter Accidents

Normally, municipalities must keep roads and sidewalks in a reasonable state of repair. If they fail to do so and someone is injured as a result, they can be held liable. However, when an SWE is declared, the municipality’s duty changes:

The clock on maintenance timelines pauses during the SWE.
The municipality is deemed to have met the minimum standard of care for that period if it:
- Monitors the weather; and
- Treats the road if the municipality decides it’s practicable to do so, and when the municipality decides it’s appropriate to do so.

O. Reg. 239/02: MINIMUM MAINTENANCE STANDARDS …

Once the SWE ends, regular maintenance standards and timelines resume.

Can You Still Sure a Municipality After a Slip and Fall or Car Accident During Significant Weather Events?

Yes. Declaring an SWE does not give municipalities blanket immunity from lawsuits. Plaintiffs can still challenge:

Whether the SWE was properly declared.
Whether the municipality acted reasonably in monitoring conditions and deploying resources.

That said, the declaration of an SWE does offer significant protection to a municipality, and the decisions that a municipality makes surrounding SWEs are largely discretionary.

It is important to keep in mind as well, that once an SWE ends, municipalities must resume with regular winter maintenance.

What to Do After a Winter Slip and Fall or Car Accident in Ottawa or Pembroke

If you are injured in Kingston, Ottawa, or Pembroke during or after a significant weather event:

Gather evidence as soon as possible: Take photos of the scene, your injuries, and any visible snow or ice.
Note the date and time of your accident—this helps determine if an SWE was in effect.
Get contact information for any witnesses.
Report your injury to the municipality promptly. You must do so in writing, delivered personally or by registered mail, within 10 days of your accident. Best practice is to have this notice drafted by a lawyer.
Consult a personal injury lawyer experienced with municipal liability cases.

Key Takeaways

Municipalities’ obligations to clear snow and ice are temporarily changed during an SWE under Ontario’s Minimum Maintenance Standards
After an SWE ends, normal standards resume and municipalities must act within set timelines.
You can still bring a claim if you believe the municipality did not act reasonably or failed to comply with its obligations.