CANNON BALL, N.D. — So far, the hundreds of protesters fighting the Dakota Access pipeline have shrugged off the heavy snow, icy winds and frigid temperatures that have swirled around their large encampment on the North Dakota grasslands.

But if they defy next week’s government deadline to abandon the camp, demonstrators know the real deep freeze lies ahead, when the full weight of the Great Plains winter descends on their community of nylon tents and teepees. Life-threatening wind chills and towering snow drifts could mean the greatest challenge is simple survival.

“I’m scared. I’m a California girl, you know?” said Loretta Reddog of Placerville, California, a protester who said she arrived several months ago with her two dogs and has yet to adjust to the harsher climate.

The government has ordered protesters to leave federal land by Monday, although it’s not clear what, if anything, authorities will do to enforce that mandate. Demonstrators insist they will stay for as long as it takes to divert the $3.8 billion pipeline, which the Standing Rock Sioux tribe believes threatens sacred sites and a river that provides drinking water for millions of people.

The pipeline is largely complete except for a short segment that is planned to pass beneath a Missouri River reservoir. The company doing the building says it is unwilling to reroute the project.