With a snowstorm bearing down on Atlantic Canada, a search and rescue helicopter equipped with night-vision gear joined the search late Saturday for an autistic boy who wandered away from his home in rural Cape Breton without a winter coat.

Seven-year-old James Delorey was apparently following the family's dog when he walked into the woods near South Bar at around 2 p.m.

The brown-haired boy, who weighs about 60 pounds, was wearing dark jeans, a blue plaid shirt and a grey vest, police said.

The temperature was hovering just above freezing late Saturday and the forecast was calling for rain and up to 15 centimetres of snow on Sunday.

Several hours after the search started, military officials in Halifax dispatched a Cormorant helicopter from Canadian Forces Base Greenwood.

The big chopper was expected to arrive on scene after 11 p.m. Staff Sgt. Jerome Kelly, spokesman for Cape Breton Regional Police, confirmed boats were searching the east side of Sydney harbour.

As well, ground search crews were joined by police officers on all-terrain vehicles. "The search will go on until we find him," Kelly said.