Just as Ontario enjoyed a brief respite from winter with rising temperatures, a formidable Colorado Low is poised to deliver a mix of heavy snow and rain across the province this week, according to forecasts from Instant Weather Inc. and Environment Canada. Residents from southern urban centers to northern communities are urged to brace for challenging weather conditions starting as early as Monday, March 3, 2025.
In southern Ontario, encompassing Mississauga, Brampton, Halton, Durham, Hamilton, Niagara, and the Greater Toronto Area (GTA), moderate to heavy rainfall is expected. The influx of rain, combined with melting snowpack, raises the risk of urban flooding, particularly in low-lying zones and areas with inadequate drainage systems.
As the system tracks northward, regions including Owen Sound, Barrie, and Muskoka may experience a shift from rain to wet snow or freezing rain overnight as temperatures plummet. Environment Canada’s models suggest this transition could complicate travel and visibility in central Ontario.
Northeastern Ontario, including Sudbury, North Bay, and surrounding areas, is forecast to face the storm’s heaviest impact, with significant snowfall accumulation, poor visibility, and treacherous road conditions. Meanwhile, northwestern communities such as Thunder Bay, Geraldton, and Kapuskasing can anticipate lighter to moderate snow, with conditions expected to ease as the system progresses eastward.
While precise precipitation totals and the storm’s full strength remain uncertain, caution is advised. Drivers north of the GTA and across central and northeastern Ontario should prepare for icy surfaces, reduced sightlines, and potential delays. Residents in flood-prone southern areas are encouraged to monitor water levels closely, while those in the north should ready themselves for winter driving hazards.
Instant Weather Inc. and Environment Canada urge Ontarians to stay informed through ongoing updates as the Colorado Low approaches. Further alerts may be issued as the situation develops.