Artillery, forecasting, tunnels and nets keep Rogers Pass (mostly) open

The military has been firing explosives into the mountains of Rogers Pass for 50 years — just one part of an ongoing program to fight the avalanches so prevalent along that stretch of the Trans-Canada Highway.

"We work with Canadian military with the C3 howitzers, so the military fire artillery rounds into the avalanche start zones," said Jeff Goodrich, an avalanche operations co-ordinator with Parks Canada.

"So we have over 250 predetermined targets that we'll fire into 134 avalanche paths that may affect the highway."

Jeff Goodrich has been watching the snow in Rogers Pass for Parks Canada since 1991. (Monty Kruger/CBC)

The goal is to trigger avalanches before they get too big, bringing the snow to rest before it hits the highway.

The man in charge of those howitzers is Sgt. Ian Taylor. He says the big guns, which fire 105-mm rounds, were deemed the most effective weapons for triggering avalanches to get rid of excess snow.

"It's a great experience," he says of the job. "Recommend it for any artillery soldier that can get a chance to come out here. It's quite an experience to see this."

Sgt. Ian Taylor is the officer in charge of firing artillery at the mountains in Rogers Pass. (Monty Kruger/CBC)

The big guns are just one aspect of keeping the highway clear through Glacier National Park.

Parks also monitors conditions and weather to forecast avalanche risks. There are snow sheds that allow avalanches to pass over the road, and during the past two years Parks has installed netting that holds snow in place where avalanches would traditionally start.

"This is our first couple of years, but we haven't had any avalanches reach the highway, and we haven't had to do any active avalanche control in these paths," Goodrich said of the netting.

Some of the netting installed in avalanche zones in Rogers Pass. (Parks Canada)

"It's quite an extensive area of netting in those avalanche start zones. It's one of the largest projects in the Western Hemisphere for avalanche netting."

The combination of measures has been successful, according to Goodrich. He says that when the highway opened, they anticipated weeks of closures each winter. But the closures have been kept to an average of 100 hours per year.

Goodrich has been watching the snow in Rogers Pass since 1991 and says understanding avalanche risks is part science, part art.

One of the snow sheds in Rogers Pass that allows snow to pass overhead and vehicles underneath. (Monty Kruger/CBC)

"With 134 avalanche paths, they each have their own personality, if you will, and over time you get to know what their characteristics and what their behaviour is under certain conditions," he said.

"You can look at all the numbers, but also the experience over time can give you the intuition of when things are developing into difficult avalanche conditions."