One man was killed and three others injured in a single-vehicle crash that completely closed Highway 2 north of Carstairs for hours on Wednesday morning.

The crash happened around 7 a.m. and closed both the northbound and southbound lanes of the major thoroughfare, also known as the Queen Elizabeth II Highway, as police and paramedics responded.

One man died at the scene, and three were transported to Foothills hospital in Calgary — one by helicopter, two by ground ambulance — according to paramedics.

EMS spokesman Stuart Brideaux said two of the injured were transported in potentially life-threatening condition, and one in serious condition.

Police said all four men were in their late 20s or early 30s.

A STARS Air Ambulance helicopter landed at the site of the collision on Highway 2 near Carstairs. (Vanessa Rifo)

All lanes of Highway 2 had re-opened by 11 a.m.

Police said alcohol is not believed to be a factor.

The investigation into the cause of the crash continues.

The approximate location of the crash. Alberta Highways said it happened on Highway 2 north of Highway 581, near Carstairs. (CBC)

Carstairs is about 60 kilometres north of Calgary.