The Minnesota winter that won't end is expected to dump up to a foot of snow in the Twin Cities by Thursday night, snarling traffic throughout the day, weighing down tree limbs and wearing out the patience of some of the state's hardiest winter afficionados.

The precipitation has started the day as freezing rain. Buses are replacing trains on the Hiawatha light rail line Thursday morning because of ice on the overhead wires.

The heaviest snowfall was expected to hit the Twin Cities between 8 a.m. and noon Thursday, creating morning commute chaos and treacherous roads, said Joe Calderone, senior forecaster at the National Weather Service in Chanhassen.

Another half-inch of snow could continue to fall into Friday, complicating yet another morning commute, Calderone said.

The heavy, wet snow could also create backbreaking work for shovelers, clog snowblowers and possibly break tree limbs and down power lines. But ice would be far more damaging, said Mary Sandok, spokeswoman for Xcel Energy, the dominant electricity provider in the metro area.

That's what many in southwestern Minnesota had to deal with when the first swipe of the storm system left some residents without power, perhaps for two more days.

Freezing rain on Wednesday toppled trees, power poles and lines, leaving at least 4,000 homes and businesses in Nobles, Rock and Murray counties and an additional 29,000 customers in Sioux Falls, S.D., without power on Wednesday afternoon. Gov. Mark Dayton called out the National Guard to help respond to the disruptions.

Hospitals, nursing homes and other vital facilities in the Worthington area relied on backup generators for electricity while utilities doled out electricity in a "rolling blackout," lighting up sections of the county for 45 minutes at a time.

Xcel Energy had restored power to 32,000 customers in the Sioux Falls area earlier Wednesday.

In the Twin Cities, the Minnesota Department of Transportation geared up its plows for the spring storm. Spokesman Kevin Gutnkecht said the goal would be to plow to bare pavement, and not rely on melting to finish the work.

"We'll treat this like any other snow event," he said. "There will be no change in strategy based on the [calendar]."

Although some social media sites lit up with posts that Minneapolis is not allowed to call a snow emergency after April 1, city officials clarified that it's not exactly true. Steve Kotke, Minneapolis' public works director and city engineer, said city officials could declare a snow emergency if needed.

But it likely won't be needed with this storm because much of it likely will melt by the time any snow emergency would go into effect Thursday or Friday night. The plows will be out in force, clearing the travel lanes, he said.

A dozen city trucks still had full plowing equipment Wednesday, down from the usual 40 at midwinter. Mike Kennedy, street maintenance engineer, said crews would reattach blades as needed.

"People think if we haven't declared a snow emergency, we're not doing anything," he said. "Nothing could be further from the truth. People won't be moving their cars out of the way, but we'll be dealing with it."

While the April snowfall is disheartening, it likely will begin a slow melt as temperatures rise to about 40 degrees on Saturday and Sunday.

More rain and snow may fall Saturday night, Calderone said. And springlike temperatures could remain elusive for a bit with long-range forecasts calling for below normal temperatures.

The good news, he said, "May comes on May 1."

Staff writers Paul Walsh and Tim Harlow contributed to this report.