When an avalanche roars down a mountain, swallowing climbers, it’s clear this is not CGI. It’s too real, dramatic and consuming.

That pretty much describes “Klondike,” the Discovery Channel miniseries airing Monday through Wednesday. The network’s foray into scripted drama is slow to start but quickly finds the right pace.

It’s a savvy choice for an epic, focusing on a chapter of history that people know, the Yukon Gold Rush, but not well. The six-hour production features characters based on real people, including a braying Jack London. It’s a drama, though, not a documentary.

“Klondike” gives what a miniseries must to keep us engaged: basic human condition. And it does not get more basic than battling the elements of an endless winter in a time before high-tech materials and portable batteries were invented.

Having defrosted from this shoot, Richard Madden (“Game of Thrones”), who plays the main character, all-around good guy Bill Haskell, was driving in Scotland to “get refrosted,” he tells Zap2it.

The miniseries opens with Haskell leaving his May 1, 1897, college graduation. He helps his friend, Byron Epstein (Augustus Prew), escape a gambling den in New York’s Chinatown, and they’re off on an adventure.

Riding in an old-fashioned train, knocking back whiskey, they don’t know where they’re heading and have nothing “but a hatful of hope.”

Initially, they have no idea what they are going to do with their pooled $750. But a stranger in a bar shows them his stash of gold nuggets, so they join those fighting the weather to scrape gold out of the Earth.

Madden wasn’t complaining about the three-plus-month shoot, but he offers this insight about lying still on the icy tundra while his beard and eyelashes froze.

“I got frostbite on my left cheek lying on the ground,” he says, “actual, genuine frostbite. If it wasn’t cold enough, they turned on huge wind machines and shoveled snow into it to hit me in the face. That just about destroyed me, and I was thinking, ‘It can’t get any worse than this!’ And they were setting me up for it getting much, much worse.”

Madden shares what it was like on Fortress Mountain in the Canadian Rockies.

“It was really steep and snowy, and the snow was so deep and the mountain so steep you would just vertically slide down until up to your shoulders,” Madden says. “And the men behind and in front of me were fine with walking. And once I sunk down to my shoulders, which put me even to the shoes of the men in front of me. And I realized he had metal clamp-ons on. Oh, come on! I think I can get away with some modern add-ons here. You can’t see my waist, never mind my shoes. The only time we cheated was with clamp-ons.”

Other than that, every costume is spot-on down to making their pants and woolen coats muddied and beaten up.

The political tenor is right, too, as Abbie Cornish (“Candy”) plays Belinda Mulrooney, a fearless woman determined to make her way in the testosterone-crazed great North. She’s a terrific shot, a visionary businesswoman, and has no use for “the lower 45,” where women can’t vote. Mulrooney is utterly in love with Haskell.

“When we meet him, he is an honest, ambitious young man, and he is doing something very daring,” Madden says of Haskell. “He is not the rebel of the two of them in the piece, but he is an educated man and doing the absolute wrong thing of what his parents would like him to do. He wants to have an adventure. He just wants to go out and follow his own heart like a lot of young men.

“He gets hardened,” Madden continues. “The more I read into his gold rush and how he got there, I expected to see how humans can be animals and the terrible things they can do. Every story, when it came to the worst cases, it tended to be human kindness that shone through. Men were starving, and others would share the tiniest bit of food, and I thought that would be just fascinating.”

As the miniseries unfolds, pretty much every emotion beyond Haskell’s determination surfaces. Even minor characters prove their hubris, courage, avarice and decency.

“Klondike” is well cast with Sam Shepard (“August: Osage County”) as a tough priest and Tim Blake Nelson (“O Brother, Where Art Thou?”) as an honorable man among thieves.

Matters turn ugly over Haskell and Epstein’s stake in the land, and Haskell spends much of the miniseries seeking justice for his friend who was gunned down. When he wheels Epstein’s body into town, Haskell asks for the law.

“Ain’t no law around here,” one man says.

Haskell, though, never gives up.

“Haskell has a great heart,” Madden says. “What is amazing is how much he gets pushed. He could take the wrong position. What I love is he always manages to pull himself back. That is what I loved about him. He is a good man. That is what fascinated me. Goodness prevails.”