BOISE -- A Boise father caught a harrowing moment on camera during a recent ski trip to Brundage Mountain.

Winston Goss posted the video to his Facebook page as a warning to other skiers.

Goss and his son Ethan were tree skiing at Brundage when the boy zoomed past him, hit a jump, then vanished beneath the snow.

Ethan had fallen into a tree well, a treacherous patch of loose snow created when a tree's lowest branches keep snow from packing into the area around the trunk. As snow settles on the branches, a deep pocket of quicksand-like snow forms beneath, often invisible to nearby skiers.

Unsuspecting skiers and boarders who get too close to the tree well can fall into it and become trapped.

Goss skied up to the spot where Ethan vanished. His son's screams were audible, but only his arm and part of his leg were visible in the deep hole.

The father was able to reach down and pull Ethan up until his head and upper body was free from the snow. With Goss' help, the skier was able to climb out of the well.

"I am so happy I was above you," Goss tells his son in the video.

In his post, Goss calls the moment "THE most frightening experience I have had as a father." He warned other skiers to be aware of the risks of tree wells, which can quickly turn deadly.

"Fortunately I was there to pull my son out," he wrote. "Please, take the time to know the dangers around you. Most importantly, never ski alone."