12/27/2025
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🚨 EASTERN & CENTRAL ONTARIO: HIGH-IMPACT Ice Storm Becoming Increasingly Likely Sunday into Monday
This is a post we were really hoping we wouldn’t have to write.
We’ve been closely watching the model data over the past few days and crossing our fingers that this scenario wouldn’t materialize. Unfortunately, the data has become increasingly locked in on what could be a significant freezing rain event for a large portion of Central and Eastern Ontario.
These are areas that know all too well the damage an ice storm can cause after last March’s crippling event that left some without power for weeks.
We know many are still recovering from that storm, and we don’t take issuing a forecast like this lightly. Even the mention of freezing rain can bring a lot of stress, especially for those who were heavily impacted last time.
At this point, models are not showing something on the same level as last March, when ice accretion approached or exceeded 30 mm in some areas. While this one could bring closer to 15-20mm in the hardest hit zone. However, this upcoming system could still bring widespread impacts. One key difference is wind. This storm looks to feature much stronger winds, which were largely absent during March’s event. On top of that, a sharp temperature drop follows the storm, meaning any ice that forms will not be going anywhere.
There is still disagreement in the models on the exact placement of the freezing rain and how far north the freezing line makes it. That detail will determine who sees the most intense icing.
Right now, freezing rain looks to begin Sunday afternoon along a rough line from Barrie through Peterborough and into Kingston. This includes much of Central Ontario and Eastern Ontario, including the Ottawa Valley.
Conditions will steadily worsen through Sunday evening as persistent freezing rain allows ice to continue building on surfaces. The highest risk for significant icing currently appears to be around Lake Simcoe, including Simcoe County, Kawartha, Peterborough, Muskoka, Haliburton, and Bancroft.
What is especially concerning with this setup is the duration. Freezing rain could persist for over 12 hours, and possibly close to 24 hours in the hardest hit areas. That kind of duration allows substantial ice accretion, putting major strain on trees and power lines. Power outages could become increasingly widespread Sunday night as the ice load takes its toll, especially in areas where the power grid is already vulnerable following last winter’s storm.
There is still a scenario where this storm ends up less impactful. That would involve above-freezing surface temperatures pushing farther north Sunday night, allowing freezing rain to change to rain and helping melt ice that has already formed. If that happens, southern parts of Central and Eastern Ontario from Barrie and Muskoka through Peterborough and into Kingston could avoid the worst impacts. However, cold air can be stubborn in setups like this, so preparation is still strongly advised.
The focus then shifts east overnight. The worst icing may move into the Ottawa Valley just after midnight as areas farther southwest slowly rise to or just above freezing. That warm-up looks brief. A surge of colder air arrives late Monday morning, changing all precipitation to snow and re-activating lake effect snow off Lake Huron and Georgian Bay.
This transition matters a lot. Areas that manage a few hours above freezing can shed some ice before temperatures drop again. Areas that do not warm up risk having that ice locked in place for days. The Ottawa Valley is a major concern right now, as current guidance suggests little to no warm-up before precipitation switches from freezing rain to snow Monday morning.
To make matters worse, very strong winds are expected to develop Monday morning and continue through the day. Gusts of 50 to 80 km/h look likely across much of Central and Eastern Ontario. In areas with significant ice accretion, this is a classic recipe for additional power outages as ice-covered branches are easily blown onto power lines.
Blowing snow and even localized blizzard-like conditions could also develop Monday with snow squalls off Lake Huron and Georgian Bay.
Some models even show wind gusts approaching damaging levels near Lakes Huron, Ontario, and Erie, with isolated gusts nearing 100 km/h.
While there is still time for the freezing rain zone to shift, freezing rain is one of the most finicky precipitation types. Small temperature differences can be the difference between a minor event and a damaging ice storm. Given the growing confidence in the models and the potential impacts, this is not something we can ignore.
Now is the time to prepare for the possibility of prolonged power outages. It may not happen, but it is far better to be over-prepared than caught off guard.
We’ll have a more comprehensive forecast with our custom maps posted later Saturday once the latest data is reviewed. Stay tuned, this is going to be a very complicated forecast.
- Brennen
