05/10/2013 02:14 EDT | Updated 07/09/2013 05:12 EDT

WW II Dambusters attack marked by Alberta museum

The Bomber Command Museum in Nanton, Alta., will be holding a special 70th anniversary commemoration on Saturday for a top secret bombing raid in the Second World War and honour an Albertan who is a surviving member of the crew.

- AUDIO: Museum director Dave Birrel talks about one of the most famous Second World War air raids.

It was called the Dambusters raid — a mission during which 19 Lancaster bombers targeted three hydro dams in the industrial heart of Germany — and it was considered a big boost for the Allied forces in 1943.

There are only three surviving bomber crew members left around the world, and one of them is Fred Sutherland, 89, now living in Rocky Mountain House, Alta.

Sutherland was 20 years old at the time of the raid and serving as a front gunner.

"I think everybody thought, 'This is it, we're going to have a lot of losses,'" he said.

A bomb from Sutherland's plane breached one of the dams.

He didn't see it explode, but the tail gunner did.

"He says, 'It's gone, it's gone' — or something like that — he couldn't believe it," said Sutherland.

'Bouncing bomb'

The top secret bombs were spun before they were dropped and skipped like stones before exploding against the dams.

The codename for the weapon developed by Barnes Wallis for the mission was Upkeep, but it's better known as the "bouncing bomb."

The approach was conducted a low altitudes — just 20 metres to avoid detection.

Nearly half of the highly trained flyers never made it home because of crashes and flak.

"Those guys had a lot of courage," said Sutherland.

The mission, called Operation Chastise, put two dams out of action for months and affected German industry.

There were also civilian casualties — a grim reality for both sides in the air war. More than 30 Canadians served on the Dambusters mission, and half of them didn't make it home.