Avalanche scenario triggers rescue exercise on Canterbury mountain

A major police-led rescue mission was carried out in Canterbury yesterday after an avalanche trapped dozens of people on the slopes. But don't be alarmed, it was all just a drill.

The Canterbury Avalanche Response Group has been in action for eight years now. A practice makes perfect, because how fast they respond dictates how many survive.

The drill was a full-scale emergency response to a massive avalanche in the unpredictable and steep alpine terrain of Canterbury's Mount Cheeseman.

"We try and make it as realistic as possible to give the rescuers a real life experience so if it does happen down the track then they have that experience that they've already built on," Senior Sergeant Antony Callon of Timaru Search and Rescue told 1 NEWS.

There was a ground crew of 50 - mostly volunteers from Search and Rescue, St John ambulance, and ski field and helicopter operators from the surrounding districts. Another 20 co-ordinated from the emergency operation centre in Christchurch.

But it could well have been be a very real response as rescue crews navigated the slopes for survivors.

Andrew Tindall of the Mt Cook Alpine Rescue Team said rescuers use transceivers and reco-devices, "whatever tools you've got". 

"There may be a foot sticking out of the ground or a glove. So you're using a whole bunch of senses, so you've got to be pretty well tuned and well practiced to actually do it well." 

It's been around four years since police last held a major avalanche exercise just like this one. And one of the major benefits is pulling all emergency services together who would have to work on the real thing.

And it's time critical. The first 10 minutes are when most people will still be found alive.

Senior Sergeant Callon said it's about finding them and triaging them back to hospital or back to the staging area.

Police say an avalanche can self-trigger and people's best chance of survival is having the right gear and knowing how to use it.

Or hoping the rescue team in yesterday's exercise are first on the scene in the seconds that follow.