It was intended to be a creative way to announce a new baby's sex to friends and family.

Instead a new father's use of colourful explosives went horribly wrong, leading to a wildfire that burned through 47,000 acres and caused more than $8 million worth of damage.

Footage released by the US Forest Service on Tuesday shows how the gimmick led to a costly wildfire in southern Arizona in April 2017 that forced about 200 people from their homes.

The "gender reveal" party was thrown by Dennis Dickey, an off-duty border patrol agent, who fired a rifle at a homemade target placed in the middle of dry grassland near Green Valley, Arizona.

Gender reveal parties are intended to announce a baby's sex to loved ones.