Icy wild weather causes havoc in Vic

Victoria has shivered through close-to-zero temperatures and endured 100km/h winds, with roofs torn off and power lines knocked out.

The SES received more than 1000 calls for help on Tuesday as the gale-force conditions uprooted trees and menaced traffic.

Snow started falling in Victoria's northwest by afternoon, with towns like Ballarat and Trentham hit by icy 2-degree blasts.

On the ski-slopes at Falls Creek, an eight-year-old autistic boy sparked a huge search after he went missing while tobogganing.

Hundreds of people joined police to look for him and he was thankfully located just after 6pm.

Areas worst affected by the buffeting winds took in the state's Bellarine and Mornington peninsulas, where tin sheeting was blown off a roof and a trailer detached from a truck at Geelong.

A large tree flattened a house in Belgrave and numerous others were strewn across roads in the Dandenong Ranges.

The SES says there were no reports of injuries but it expects calls to increase with people returning to homes on Tuesday evening.

"Wind is the main trigger," SES spokesperson Marc Dorey told AAP.

"It seems to have eased a little bit but we expect more calls as people come home at the end of peak hour and become aware of issues," he said.

The chilly temperatures weren't likely to arrive in Melbourne until late Tuesday night or early Wednesday.

The Bureau of Meteorology warned of more damaging thunderstorms, hail and strong winds, especially in coastal areas, as a major low pressure system continued its sweep across the state.

Winds should subside from late Wednesday morning but the big freeze will remain.

"Wind chill is expected to be extreme through Melbourne. It will feel like zero through most of the day," said the bureau's senior meteorologist, Adam Morgan.

The SES is warning drivers to be on the lookout for black ice and drive to conditions.