06/27/2015 12:44 EDT | Updated 06/27/2016 05:59 EDT

Canmore house explosion likely caused by gas leak

A gas leak is likely responsible for an explosion that shook the Alberta mountain town of Canmore, blowing up an unoccupied home, scattering debris on the streets and leaving as many as 40 people with minor injuries.

Town officials suspect a gas leak was ignited on 13th Street at about 5 p.m. MT on Friday. The large boom and a plume of smoke startled residents throughout the town.

One woman who was picking up her grandchildren on the street said she smelled gas about a half an hour before she heard the thunderous explosion. Now she can't return to the house.

"We can only see pictures, we can't get to it, but the windows and the doors are out," said Theresa Biggy.

About 430 homes and businesses in Canmore are without gas and a handful of homeowners on the street are not allowed to return to their home.

Clean up has begun on the street and an engineering firm is checking nearby homes to make sure they are safe.

An many as 40 people hurt

A town official said the explosion happened next to a construction site by a seniors' home at Fairholme Drive and 13th Street. Utility workers were doing work in the area at the time. All of those workers are accounted for, say RCMP.

The home, which was empty, was reduced to a pile of rubble. A second home was also badly damaged, with even more houses in the neighbourhood experiencing minor damage. The streets — and even rooftops —  were strewn with debris.

Three people went to hospital with minor injuries. ​RCMP estimate about 40 people had minor scrapes and cuts from flying glass and debris.