On a perfect blue sky day, a helicopter darts above the awe-inspiring peaks of the Icefields Parkway.

Though just a tiny spec in comparison to the mountainous terrain, inside the helicopter sit members of Jasper National Park’s (JNP) public safety crew.

With a spotter in the front, the eyes of the operation, and two or three people in the back managing explosives, the crew is controlling the risk of avalanches on the road by dropping bombs to trigger slides.

First the crew will fly by the slide paths, to ensure a safe flight path and pick out the targets along the mountain, explained Steve Blake, public safety manager for JNP, who describes the process.

“The one person at the door (which is currently off the helicopter) will pull two of the wires, the other person will pull the third. Me, in the front this time, I would say ‘we’re five seconds out, three, two, one, drop.”

“The bombs are big and it’s not as simple as handing them out the door,” explained Blake.

Blake and his crew were out last Tuesday ensuring the safety of drivers on the parkway, which he estimates has seen up to twice the amount of snow as this time last year.

So what is Parks’ response to these unusual conditions?  Use bigger bombs.

“The conditions were such that there was a lot of snow... we needed big things to get the results we needed.”

With the road closed, public safety crew members would build the bombs on the road while others were out blasting the peaks. The crew was using large bags of ANFO, which is a concoction of diesel and fertilizer that had smaller explosives inside.

“ANFO is very stable. You could throw it out of the sky and it would just break open like a bag of fertilizer, because that’s actually what it’s made of. So, you have to put a smaller explosive inside of it to make it hot enough and concussed enough to blow up,” said Blake.

However, it’s not just the amount of snow that is making conditions a little unusual this year, it’s also the consistency of the snow.

“It came in so fast it’s very solid and stable,” said Blake. “That means it settles quicker and it sticks a little bit quicker - the way you make a snowball... it actually has some strength to it where as on a cold weather storm it comes in and it just stays sugar, it doesn’t want to stick, that’s actually why you get avalanches – you’ll get a layer of sugary snow and then you’ll get some warm snow that settles and makes a consistent slab.”

In total, the crew used about 45 explosives that ranged in size between nine and 25 kilograms to target some of the 50 avalanche paths that could affect road conditions. For Blake, that’s an “ideal bombing run” particularly because the paths were cleared without any debris on the road.  This ensues there will be less avalanche risk after the next storm.

“We got good results, our paths are cleaned out, so this next storm here, can do a lot of things without even creating a worry for us.”

For Parks Canada, the control of the slide paths is an important facet of their winter work, so travellers can use the parkway with little concern.

“Your average drive on the highway is assuming that those risks are not present, so that’s standard in Western Canada,” he said noting that there were different approaches for avalanche control depending on location. Avalanche control for highway safety is different than managing avalanches on a ski hill.

“You want to get rid of the weakness in a avalanche. For a highway program you’d love to see grass growing in your start zones because you know you have nothing to worry about. At the ski hill, for example, they need to make sure the snow is safe but they don’t want to slide their paths to ground because those are ski runs.”

Blake also stressed that Parks does virtually no avalanche control in “wildland areas” but instead issues daily avalanche reports that are “strictly information.”

“[Others] make conscious decisions to do activities on certain terrain and our daily avalanche bulletin is geared towards helping them make better decisions,” said Blake.

Those looking for the current avalanche bulletin can visit www.avalanche.ca.