Unseasonably warm weather last week melted the remaining man-made snow at Tussey Mountain Ski Area, closing the slopes for four days and forcing ski classes indoors.

Two slopes will reopen today.

Although the early onset of winter allowed Tussey Mountain to enjoy favorable business in December, above average temperatures in January and February have had a negative impact on the ski season. To make snow, temperatures must be below 28 or 29 degrees with low humidity, said Tom Impellitteri, a ski instructor.

The warm weather "has taken 90 percent of the snow we had --which is most everything," said Tussey General Manager Dan Torsell.

Man-made snow has helped Tussey Mountain remain open this season since the area has not received heavy snowfall, Impellitteri said.

Accu-Weather Meteorologist Paul Yeager said temperatures have been averaging nine degrees above normal since Jan. 1.

"Every day this month through (Feb. 16) has been above normal," he said. The average high in February has been 35 degrees.

Last week's University physical education classes were forced to alter schedules. University ski students met indoors at the Tussey Mountain Lodge to hear a lecture series, Impellitteri said.

Colder temperatures during the weekend made artificial snow production possible again.

"It was down to eight degrees last night and we made a ton of snow," Torsell said.

Tussey Mountain plans to reopen two trails, the Utah and Beginner slopes, at 3 p.m. today. Employees spent yesterday preparing the two slopes, which are "looking good," Impellitteri said, adding, "It's definitely 'ski-able.' " However, other trails are still covered with patches of dirt and snow.

Avid skiers do not need to worry that the season will be a washout, Torsell said.

"Tussey Mountain is committed to operating through the third week of March," Torsell said. "A lot of people thought we'd be closed down (for the season)."