Heavy snowfall forced northern Italy to close briefly its major airports on Wednesday, including Milan Malpensa Airport.

Up to 40 cm (15 inches) of snow has fallen across northern Italy since Tuesday, slowing the return to work after the New Year holiday.

"Things are not expected to improve until Friday," a spokesman said.

Milan's Linate Airport put a halt to flights until early afternoon, as did Orio al Serio in nearby Bergamo and Caselle in Turin.

Although major roads were mostly clear, traffic in some parts of Milan was snarled due to trees that had fallen under the weight of the snow, the regional emergency authority said.