Blacktail Mountain Ski Area near Lakeside announced Thursday it will open Dec. 18.

Steve Spencer, the ski area’s general manager, said he had been hoping to open this weekend, but the system of warm weather at the beginning of the week delayed the opening.

“We had the Pineapple Express come through here and had rain all the way to the top,” Spencer said. “This morning it was pretty much a sheet of ice, but it’s been snowing all day and getting covered up real well.”

Blacktail’s opening is later than usual, he noted, but all of the runs should be open. By midafternoon Thursday, he estimated the mountain had received three inches of new snow.

“We could open the top half right now, but I think it’s a little early to do a marginal opening. I’d rather have a good-quality first day.”

According to Blacktail’s website, the mountain is forecast to receive significant snowfall over the next several days and had a settled base of 25 inches Tuesday.

Whitefish Mountain Resort opened Saturday and had five chairlifts and 10 runs open Thursday.

Riley Polumbus, the resort’s spokeswoman, said more terrain could open by this weekend as more snow accumulates on Big Mountain.

“The storm got going around 11 this morning,” she said Thursday afternoon. “Our snow reporter estimates about an inch an hour in the village.”

Big Mountain has received a foot of snow this week.

Snow reports for Blacktail can be found by visiting blacktailmountain.com.

Whitefish Mountain Resort posts snow reports at skiwhitefish.com/snowreport, and skiers and snowboarders can also call (406) 862-SNOW for updates.