There are some events so tragic and catastrophic they can rock an entire nation.

The bombing of the twin towers on 9/11. The death of Terry Fox in the middle of his cross-country marathon.

And the first Canadian casualties in Afghanistan – four soldiers killed by friendly fire.

It’s been a decade since Sgt. Marc Leger, Cpl. Ainsworth Dyer, Pte. Richard Green and Pte. Nathan Smith died on Afghan soil by the hands of U.S. pilot Maj. Harry “Psycho” Schmidt — who was later convicted of dereliction of duty.

The troops, all members of the Princess Patricia’s Canadian Light Infantry, were firing weapons at a training range in Kandahar on April 17, 2002, when Schmidt mistook them for hostile forces and dropped a bomb on them.

They were the first Canadian soldiers to be killed in a combat zone since the Korean War — just two months after Canada sent 850 troops to the region as part of Operation Enduring Freedom.

Their deaths were a tremendous shock, but the reality that a bomb dropped by friendly forces had killed the four men and wounded eight others, was an added blow.

Close friend and fellow soldier with Edmonton-based Third Battalion of the Princess Patricia’s Canadian Light Infantry Daryl Bonar says the case reminded the public that Canadian troops were once again facing real dangers.

“When it happened I was devastated, along with the rest of the country,” said Bonar, who was on an earlier tour in Bosnia with the four men.

“The first four casualties really put things into perspective.”

Today, the fallen four remain in the hearts and minds of people across the country.

Though they’re memorialized every year on the anniversary of the friendly-fire incident, Bonar says he doesn’t need a date on a calendar to remind him to honour their memories.

He, like the family members they left behind, carries the soldiers with him every day.

“I don’t need a ceremony to remember them,” said Bonar, now a Lieutenant.

“I think of them all frequently, they had an impact on who I am today.”

Bonar was particularly close to Cpl. Ainsworth Dyer — who he describes as a charismatic and natural leader — and though it’s been 10 years since he’s seen his old friend, he can recall his face in detail.

“My regular run takes me right by his bridge almost on a daily basis,” said Bonar, referring to the pedestrian bridge renamed the Ainsworth Dyer Memorial Bridge in honour of the corporal.

“I always stop and salute Ains as I pass.”

Before shipping out to Afghanistan, Dyer had proposed to his sweetheart, Jocelyn Van Sloten, on the footbridge over the North Saskatchewan River between Rundle and Gold Bar parks.

The memorial bridge has become the site of one of Edmonton’s most touching Remembrance Day tributes — organized by Aart Von Sloten, the father of Dyer’s fiance.

On November 11 a field of wooden crosses — one for every soldier killed in the Afghanistan war — is erected near the bridge and hundreds of people turn out to pay their respects.

Many of Dyer’s family and friends will make the trek out to Rundle Park on Tuesday, but Bonar’s not sure if he’ll be joining them this year.

“I will honour him, all of them, in some way,” said the former Edmonton mayoral candidate. “It was a privilege to have known them.”

In Stittsville, Ont., Sgt. Marc Leger’s parents will pay tribute to their son in a mass dedicated to his memory.

It’s a tradition they’ve never missed, but this year on the 10th anniversary of Leger’s death, his mother says it will be more painful than ever.

“There’s no closure, you just learn to live with the tragedy,” said Claire, who was issued the Memorial Cross in 2005. “It seems like yesterday but in other ways it feels like forever.”

Similar memorials are expected to be held in Nova Scotia, for both Pte. Richard Green and Pte. Nathan Smith.

Though it’s more difficult to face the grim anniversary than most can imagine, Claire takes comfort in the knowledge that Canada’s combat troops are finally home.

The family has been placing a small Canadian flag in their front garden for every Canadian soldier who dies in Afghanistan. Last year, there were 155. Since then three more soldiers have been killed.

“We’re so sorry for all the deaths that came after,” said Claire tearfully, adding she hopes the decade of fighting was worth the Canadian blood spilled.

Though the combat troops were pulled out in 2011, like most North Atlantic Treaty Organization (NATO) allies active in Afghanistan, Canada won’t wind down all of its military involvement in the region until 2014.

angelique.rodrigues@sunmedia.ca