A major winter storm is sweeping across northeastern Ontario Sunday, bringing a treacherous mix of heavy snow, high winds and freezing rain that is expected to make travel dangerous and could lead to widespread power outages. Environment Canada has issued orange winter storm warnings for a vast swath of the region, with impact levels ranging from high to extreme. The hardest-hit areas are forecast to see total snowfall accumulations of 40 to 80 centimetres. Communities in this extreme-impact zone include Sault Ste. Marie, Timmins, Batchawana Bay, Chapleau, Cochrane, Elliot Lake, Englehart, Foleyet, Gogama, Iroquois Falls, Kirkland Lake, Searchmont and St. Joseph Island. “Travel will likely be extremely hazardous and some routes will likely be impassable,” said meteorologists in the alerts for these regions. “Roofs are at an increased risk of collapse under the weight of snow,” added the weather authority in its alerts. For these communities, all travel and outdoor activities should be avoided if possible. For a broader swath of the region, including Greater Sudbury, North Bay and Manitoulin Island along with French River, Mattawa, Powassan, West Nipissing and most areas directly east of Sault Ste. Marie, the storm’s impact is rated as high. These areas are bracing for a messy combination of 10 to 20 centimetres of snow and ice pellets, along with 6 to 12 millimetres of ice build-up from freezing rain. “Travel will likely be hazardous,” the alert read Sunday morning. The weather warning for these regions also notes possible road closures and utility outages. Travellers can obtain current road conditions by calling 511 or by visiting the Ministry of Transportation’s 511on.ca website. Across the entire northeast region, the storm is being driven by a major Colorado low bringing powerful northeasterly winds gusting up to 70 or 80 km/h, creating near-zero visibility in heavy snow and blowing snow. The alerts advise that travel on the major arteries of Highways 11, 17 and 101 will be significantly impacted. The timing and nature of the precipitation will vary. In the high-impact zone, which includes areas like Greater Sudbury and vicinity, the storm began Sunday morning. Precipitation is expected to start as rapidly accumulating snow before transitioning to freezing rain or ice pellets Sunday night. Some of these areas could even see a brief warm-up to rain Monday morning before the snow returns later in the day. For the extreme-impact zones, including Timmins and Cochrane, the storm is set to begin later Sunday and continue through Monday night. While the primary precipitation will be snow, there is a chance of freezing rain or ice pellets. For the corridor from Sault Ste. Marie to Kirkland Lake, there is an increased chance of freezing rain, likely reducing the total snowfall accumulations in this area. Other regions under winter storm alerts, such as Dubreuilville, Hearst, Kapuskasing, Moosonee, Smooth Rock Falls, Wawa and White River, can expect snowfall accumulations of 20 to 40 centimetres. Meteorologists offered similar advice for these areas: avoid non-essential travel and outdoor activities. Residents across the northeast are urged to continue monitoring alerts and forecasts issued by Environment Canada for updates. Severe weather can be reported by email to ONstorm@ec.gc.ca or on social media using the hashtag #ONStorm.