US, Canada: Storm system to bring heavy snowfall, strong winds, and ice to portions of the US and Canada through at least Dec. 30

Event

A storm system is forecast to bring heavy snowfall, strong winds, and ice to portions of central and northern US and south-central Canada through at least Dec. 30. The affected areas in the US include Utah, western and northern Colorado, southern Wyoming, northern and central Kansas, Nebraska, South Dakota, North Dakota, Minnesota, Wisconsin, Michigan, Iowa, far northern Missouri, far northern Illinois, far northern Indiana, and far southern Manitoba and southern Ontario in Canada. As of the afternoon of Dec. 24, snow is falling across eastern Ohio, eastern Kentucky, and eastern Tennessee in the US while rain is falling farther east. Forecast models indicate rain is expected to change to snow is expected to change over to snow in the coming hours from west to east. There is also likely to be a period of sleet and freezing rain in western Pennsylvania, northeastern Ohio, southeastern Ontario, and central Quebec. Lake-effect snow will persist near Lake Erie, Lake Huron, and Lake Ontario through late Dec. 25 or early Dec. 26. Some uncertainty remains in the forecast track of the system and projected snow amounts are subject to changes over the coming days.

Government Advisories
As of Dec. 28, the US National Weather Service (NWS) has issued winter storm warnings for far southwestern Colorado, far southeastern Wyoming, and central Iowa. Winter storm watches are in effect across southwestern Wisconsin, eastern Iowa, and far northwestern Illinois. Winter storm advisories in place across southern Utah, central Colorado, southeastern Wyoming, northern and eastern Kansas, Nebraska, southeastern South Dakota, southern Minnesota, northwestern Iowa, and far northwestern Michigan. Additionally, Environment Canada has issued snowfall and warnings across south-central Ontario. Authorities will likely issue new alerts or update/rescind existing advisories as the winter storm transits the region over the coming days.

Hazardous Conditions
The latest forecast guidance indicates that accumulations of 30-61 cm (12-24 inches) of snowfall are expected in the hardest-hit areas, including portions of the Great Basin and Central Rockies regions. Accumulations of 10-15 cm (4-6 inches) are expected across the Midwest, locally higher totals of 30 cm (12 inches) are possible. Lower snowfall totals are possible where sleet and freezing rain mix with snow including portions of northern Illinois. Additionally, ice accumulations of over 0.6 cm (0.25 inches) are possible across southeastern Nebraska, northeastern Kansas, northern Missouri, and southern Iowa. In addition to the heavy snow, strong wind gusts are likely to lead to periods of blowing and drifting snow. Blizzard conditions are possible. Sporadic power outages are possible throughout the affected area.

Transport
The inclement weather will likely cause widespread ground and air transport disruptions across the affected area through early Dec. 26. Traffic and commercial trucking delays are possible along regional highways including the I-29, I-70, I-80, I-90, and I-94 corridors in the US, as well as the Trans-Canada Highway. Difficult and potentially dangerous driving conditions are also likely on secondary and rural roadways in the affected states as maintenance crews prioritize clearing major routes. Authorities could close stretches of highway if driving conditions become too hazardous. Gusty winds may threaten to topple high-profile vehicles throughout the affected area. Heavy wet snow and strong winds could bring down power lines and trees with foliage. Flight delays and cancellations are likely due to ground stops and deicing operations at regional airports.

Advice

Monitor local media for updated weather information. Verify road conditions before driving in areas where heavy snowfall is forecast. Allow extra time to reach destinations in these areas and carry an emergency kit and warm clothes if driving is necessary, especially on secondary or rural routes that could become impassable. Plan accordingly for delivery delays if routing shipments by truck through the affected area through at least Dec. 30. Confirm flights. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

US National Weather Service
US Road Conditions
Meteorological Service of Canada