COEUR d’ALENE — Bundle up.

A cold wave bringing subzero temperatures is projected to reach Coeur d’Alene on Friday.

The National Weather Service, as of Wednesday afternoon, was predicting -10 degrees Friday, -14 on Saturday, -10 on Sunday and -6 on Monday.

The highs during those four days are projected to be single digits.

“It’s going to be cold, dry and windy,” Coeur d’Alene Climatologist Cliff Harris said Wednesday.

He expects about 1 to 3 inches of snow today, and then four days of subzero conditions, around -5 to -10.

Western Montana could see temperatures as low as the -30s, Friday through Sunday, according to the NWS.

“This is really quite a cold wave coming,” Harris said, who expects more snow next week when it may warm up to the 20s.

“People are going to have to be careful,” Harris said. “This is nothing to fool around with.”

Forty-five mph winds snapped branches and knocked over trash cans Tuesday. The gusts also flipped a plane at the Independence Point dock, nearly sinking it.

Crews used floats Wednesday to get the plane back on the surface.

With the deep freeze on the way, officials are urging people to be prepared for what could be life-threatening conditions.

Kirstin Haley, R.N, trauma injury prevention and education coordinator at Kootenai Health, said the extreme cold “can be very dangerous.”

She said the colder it is, the harder and faster it can hit someone.

People run the risk of hypothermia within 30 minutes of being outside if they're not bundled up accordingly, Haley said.

"Hypothermia can set in really quickly," she said.

For those wishing to exercise outside when it’s subzero, such as running or skiing, Haley said if they’re used to being outdoors when it’s cold and are relatively healthy, it could be fine.

“If you’re new to it, I would definitely say no,” she said.

Cold, slick conditions create icy sidewalks, streets and trails and increase the risk of falling, so Haley said it’s important to be careful and not go out alone.

For the elderly, it’s best to just stay inside rather than risk a tumble outside and having difficulty getting up in freezing weather, Haley said.

Falling is the No. 1 trauma that patients are treated for at Kootenai Health.

Todd Feusier, Coeur d’Alene Street and Engineering Department director, ordered a citywide plowing Tuesday to clear snow so it doesn’t freeze and create ruts.

The city generally doesn’t plow unless there is at least 3 inches of snow.

Feusier said the city will have equipment and crews ready to respond quickly during this cold snap.

Harris said cold temperatures like this are “pretty unusual for having El Niño.”

He noted there wasn’t a day with temperatures under 21 degrees in October, November or December, so the frigid temperatures over the next several days are "going to be a real shock to people.”