Police in Cape Breton say they are suspending efforts to find a missing autistic boy for the night, after heavy snowfall kept a helicopter from joining the search on Sunday.

Canadian Forces Base Greenwood was to dispatch a search and rescue Cormorant helicopter equipped with night-vision gear, to help find the boy. But poor visibility grounded the chopper, according to Staff Sgt. Ken O'Neil with the Cape Breton Regional Police Service.

"The weather conditions here stayed the same. They're just starting to diminish a little bit now, but right now darkness is setting in," O'Neil told CTV.ca by phone. "I think we're going to shut down this evening and go back at it tomorrow morning," he said.

Seven-year-old James Delory went missing around 2 p.m. Saturday. Investigators believe he followed his family's dog when it walked into the woods near the family home near South Bar.

Delory, who is described as having brown hair and weighing about 60 pounds, was wearing dark jeans, a blue plaid shirt and a grey-coloured vest. He was not wearing a winter coat, a hat or mittens, adding to the urgency of the search.

As of 4:41 a.m. local time Sunday, Environment Canada was calling for "significant snowfall" of up to 15 cm across Cape Breton County on Sunday. By 4 p.m. in the afternoon, the forecast said an additional two cm of snow would fall overnight, with a low of -2 degrees Celsius and winds gusting up to 50 km/h.

At least two hundred people braved the snow storm to help with the ground search, O'Neil said on Sunday afternoon. Earlier in the day, he told CTV.ca that flurries were already making conditions in the area "wet and slushy."

"Obviously with our ground search people, clothing would be an issue, and in that regard probably some heavier clothing (will be necessary) for those folks," O'Neil said. "But it won't change our patterns. We will continue on and hopefully we can find James."

Ground search teams were combing the rural, wooded area adjacent to a number of communities, including the city of Sydney and the Atlantic Ocean, O'Neil said.

Boats were also out on the water Saturday night, searching the east side of Sydney harbour.

With files from The Canadian Press