RENO, Nev. -- Lake Tahoe ski resorts are making up for what Mother Nature has failed to provide.

Resort operators say their ability to make snow has been a savior this holiday season, when skiers flock to the mountains over the busy Christmas and New Year's holidays.

December is typically one of the more important months for snowfall in the Sierra. But this year has been a disappointment.

On Christmas Day, the Lake Tahoe Basin's snowpack was only 37 percent of average for the date, the Reno Gazette-Journal reported.

But there is some good news. Dry conditions were matched with cold temperatures, allowing those resorts investing in snow-making capability to open substantial terrain for the busy holiday period.

"We had some real strong windows that allowed us to make a ton of snow," said Mike Pierce, marketing director at Mt. Rose. "Yes, we'd love to have more snow, but we do have what people are looking for right now."

That's the case at Heavenly Lake Tahoe and Northstar California, both owned by Vail Resorts Management Co. The two resorts, one on Tahoe's south shore and the other north of the lake, offer the two largest snow-making systems in the West, Vail Resorts spokesman Russ Pecoraro said.

At Heavenly, snow guns can cover 73 percent of the massive resort with man-made snow, Pecoraro said. On Christmas, Heavenly was operating 19 lifts in both Nevada and California, accessing more than 13 miles of skiable terrain.

Obviously, more natural snow would be a plus.

"We would certainly love that, but we can't count on it so we're going to continue to make snow," Pecoraro said. "When people come up for the holiday season, we will definitely have them covered.

"Snow-making is what makes the difference," Pecoraro said.

The folks running Squaw Valley and Alpine Meadows, which combined operations in 2011, echo that sentiment.

Among some $70 million worth of mountain upgrades pursued at Squaw and Alpine is a substantial commitment to expand snow-making capabilities, with $5.2 million spent toward that purpose since 2012.

"It's a major priority to ensure we can deliver a positive guest experience," Squaw spokeswoman Amelia Richmond said. "The snow-making is critical. It's really our insurance policy."