"This is a bit like Russian roulette."

Ben Firth, a professional mountain climber from Alberta, Canada, is in Iceberg Alley off the coast of Newfoundland to scale an iceberg.

At the small fishing community of Conche we discover a 'growler' around the size of a family house. It's been sitting in a calm bay just a few hundred metres from the shore for several days, so we're sure it's securely grounded.

Quickly into his gear and into a skiff, Ben circles the iceberg a couple of times to get his entry point. Legs straddling the bow of the boat, crampons poised, Ben nudges up to the berg and climbs onto it. After a few tentative steps, it feels secure and he works his way up the ridge to the summit, then climbs down its sheer face using his ice axes to support his weight.

Each blow of an axe sends a shower of ice. But the berg still seems to be holding up.

Suddenly, there's a loud crack. A large piece on the far side of the growler plunges into the sea. Ben reacts fast and gets up onto the flat surface of the berg just as it begins to tip.

As it rotates he runs up it and for a few terrifying seconds it looks like it's going to completely turn turtle. But it stabilises halfway through and he signals to the boat to get him.

He's done it. But only just.

"I'd say it's one of the most challenging things I've ever done. I'm wracking my brain trying to make this as safe as possible but it's hard to explain just how volatile these things are. No matter what you do to prepare you're still looking at something completely unpredictable."

For an exhilarating experience that's far less risky, book a Mazda test drive.

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