Welcome to Volcanology 101.
Mount Meager — just north of Pemberton — has several active fumaroles, which is volcanologist-speak for holes on or near volcanoes that emit gases. There is no danger to the public, but the dormant volcano is being watched.
The fumaroles were observed in July by someone in a helicopter that passed over the area.
"This is new to us," said Melanie Kelman, a volcanologist with National Resources Canada who works in Vancouver.
"In this case, there are holes in the ice and gases seem to be venting," she said. "There were some new gas vents that hadn't been seen before."
Kelman said air samples around the fumaroles — plus samples from the ice atop Meager — were taken, with results that identified hydrogen sulfide, a toxic. But there was no sulfur dioxide gas detected, which would point toward seismic activity, she said.
"Either there is thinning of the ice for other reasons, or because the heat of the fumaroles has changed and has made them come through the ice — the fumaroles weren't obvious before," Kelman said. "But because of reports of sulfurous vapours going back decades, we think they were probably there."
Kelman said that talks with scientists who worked in the area going back three or four decades revealed there were reports of sulfurous vapours and of people getting headaches from the smell.
"We think the fumaroles have probably been present but possibly weren't exposed," she said.
Mount Meager — and some other area dormant volcanoes, Mount Cayley and Mount Garibaldi among them — have had landslides over the decades.
"We've had a number of big historic slides in the area, including the big one at Mount Meager in 2010 — that's been an ongoing issue," Kelman said. But she said there has been no change in volcanic activity.
"We have an extra seismic station up there now so that we can detect smaller events and locate them better. It's something to watch and it's one more thing we can measure to sort of get the pulse of the mountain, so if anything does change in the future we'll have data to compare it to," she said.
Ryan Wainwright, Squamish-Lillooet Regional District emergency manager said people should stay away.
"Even on a non-volcanic day, Mount Meager is dangerous," he said. "If folks were to go out there and glacier climb, then we want them to be aware that this isn't the place to do it right now. It's been kicking up a bit of steam."
• Oct. 20 at 10:20 a.m. the Great ShakeOut earthquake drill, in which millions of people around the world practice the drop, cover and hold on drill, will take place. You can register for B.C.'s drill at shakeoutbc.ca.