The Chicago area is under a winter weather advisory through the afternoon and evening rush hours and dangerous travel conditions were already reported across the area as snow began falling.
The advisory, which began at 9 a.m. and continues until 6 p.m. for several counties, warned of slick road conditions and reduced visibility as bursts of snow moved across northern Illinois.
By noon, the weather service reported the area was entering "the period of steadiest snow."
Slushy accumulations are possible, especially on grassy areas, but motorists are still advised to use caution as snow begins to fall.
"Webcams across the area show snow sticking to roads and low visibility, such as near Mendota, Rockford, Lowell (IN)," NWS tweeted. "Take it slow on ice and snow!!"
Heavier snow was expected to continue until around 3 p.m. before snow begins to gradually come to an end during the evening hours. Up to one-half inch of snow per hour could fall at times, especially in western and northern areas.
By 1 p.m. several suburbs had already reported more than an inch or two of snowfall. Some accidents were reported, but the cause of the crashes was not immediately known.
"Be cautious on the roads and be sure to increase distance between you and other vehicles," the weather service wrote.
The Indiana Department of Transportation in northwest Indiana reported "roads are pretty consistently slick/slushy across our district right now."
"Visibility is also low due to heavy snow," the department wrote on Facebook Tuesday afternoon while urging drivers to increase stopping distances and decrease speed.
Here are some tips for what to do if you have to drive in winter weather.
The Illinois Department of Transportation recommends that drivers:
- Always wear a seat belt. It’s the law in Illinois.
- Slow down. Slower speeds, slower acceleration, slower steering and slower braking all are required in winter driving conditions.
- Drop it and drive. Put down the handheld devices – it, too, is the law in Illinois.
- Don’t crowd the plow. A snowplow operator’s field of vision is restricted. You may see them, but they may not see you.
- Avoid using cruise control in snow and ice.
- Watch out for black ice on roads that appear clear but can be treacherous.
- Be especially careful approaching intersections, ramps, bridges and shady areas. All are prone to icing.
- Do not travel during bad weather unless absolutely necessary. If you do have to make a trip, check the forecast and make sure someone is aware of your travel route. Consider taking public transportation if it is an option.
- Prepare an emergency kit that contains jumper cables, flares or reflectors, windshield washer fluid, a small ice scraper, traction material, blankets, non-perishable food and a first-aid kit.
- Carry a cell phone and a car charger in case of emergency.
- Follow Scott’s Law. Slow down and move over for stopped emergency, construction and maintenance vehicles.
AAA released similar precautions for traveling in snowy conditions:
- Drive slowly
- Increase your following distance by five or six seconds
- Apply firm, steady pressure on your brake
- Don't use cruise control
When roads are icy, AAA recommends:
- Be careful on bridges and overpasses, they freeze before the road
- Avoid unnecessary lane changes
- Drive, turn, and brake slowly
- During a skid, keep your eyes on the road, and don't slam on the brakes