As a powerful winter storm threatens to dump significant snow and ice across the Baltimore region, Towson University is delaying the start of its spring semester, canceling classes and urging students to postpone their return to campus.

The university announced Thursday it will be closed from Sunday through Tuesday and all classes will be canceled.

The university suggested students living on campus delay moving back for the spring semester until Tuesday, according to its website.

Bowie State University also canceled classes for Monday.

The latest predictions show snowfall will start Saturday night and continue into Sunday, with at least 5 inches of snow and possibly more than 10, the National Weather Service said Thursday. Significant ice accumulation is also possible on Sunday south of Interstate 70.

The worst-case scenario for the region is up to 18 inches of snowfall if there’s no mixing of sleet and freezing rain, said Cody Ledbetter, a meteorologist for the National Weather Service’s Baltimore/Washington office. That is less likely, because the forecast indicates at least some mixed precipitation starting Sunday morning, Ledbetter said.

The region can expect at least 3-6 inches of pure snow, he said.

Some events are being canceled.

The Orioles canceled Saturday events of the annual Birdland Caravan. Additionally, because players were scheduled to arrive in Baltimore from around the country, some originally scheduled participants won’t make appearances Friday. An event on Friday is also canceled: The Oriole Bird and Mr. Splash will no longer hold a meet and greet at the Bel Air Weis Market.