Cold snap brings spring snow to Tassie

Parts of Tasmania have been turned white by a blanketing of spring snow and forecasters say more is on the way.

A cold snap brought freezing temperatures across the state, with the mercury atop Hobart's Mount Wellington dropping to a year-low of minus 6.4 degrees on Tuesday night.

Snow fell as low as 100m in central, far southern and western areas.

The snowline is expected to rise to around 1000 metres on Thursday but drop back down to 200m on Friday as more icy weather hits.

Bureau of Meteorology senior forecaster Tim Bolden said windy September cold fronts are the norm but snow at those levels is not common.

"We do see it occasionally," he said.

"But at 200 metres, you wouldn't expect that every year."

Further snow on Mount Wellington was certain heading into the weekend, Mr Bolden said.

Police have closed several roads around Cradle Mountain and have issued warnings for potentially deadly black ice on roads in the state's west, north and far south.

The BoM has advised bushwalkers of hazardous conditions in western and central plains.