Sensing the excitement Thursday in the eyes of Mt. Bachelor’s Tom Lomax and Ryan Gage was an easy task.

It’s been a tough fall to make snow for Lomax, Bachelor’s director of mountain operations, and Gage, the mountain’s grooming manager.

But as the first major winter storm of the season approached Central Oregon, Lomax and Gage knew they were about to get extremely busy making snow.

At Mt. Bachelor, which since 2002 has used machines to make snow on its Thunderbird run, around the Pine Marten lift, and the ski area’s terrain park and halfpipe, snow-making usually starts in early November.

But this has not been a typical year.

Since snow-making season started, Mt. Bachelor’s grooming crew has enjoyed two solid stretches of 24 hours apiece where temperatures were right for snow-making.

“The rest of that time it has been pretty marginal, as far as production goes,” Lomax said on a quiet Thursday at the West Village Lodge. “We have had a lot of weather inversions where we’ll get warm air that will come in at the higher altitudes, and it pushes the cold air down and it settles here on the base area. So there is a little bit of an elevation, 200, 300, 400 feet, where it is cold. So sometimes we’ve been making snow in that.”

Through Thursday, Mt. Bachelor had used 1.8 million gallons of water to cover the 17 acres covered by its 13 snow-making stations.

It sounds like a lot of water — but barely half of what is needed. It takes about 3 million gallons of water to layer the areas with a foot of man-made snow, Lomax said.

Still, with the storm approaching, the ski area plans to open today, nearly three weeks later than what had been initially planned.

“The hurdle has been not only dry, but dry and warm,” Lomax said. “We would be in a whole different situation if we would have come in dry and cold this year. We would have something going on T-bird already.”

Gage’s grooming crew of 29 workers handles Mt. Bachelor’s snow-making duties.

But Gage and Lomax, both Bend residents who work full time at the resort, must be part meteorologists to do their jobs.

With all its advances, snow-making still comes down to weather.

Mt. Bachelor uses four permanent towers and nine stations that make snow with portable automated guns. Each is connected with the base of the mountain with a water line and a power line.

The automated guns and the towers each do their own weather tracking. Gage also collects data from three mountain-based weather stations.

Calm, clear and cold makes for the best snow-making conditions, Gage said.

The lower the humidity, the higher the temperatures can be to make snow. For instance, if the humidity is below 30 percent, snow can be made up to 34 degrees, Gage said.

Higher humidity has the opposite effect.

“Even at 28 degrees, you are blowing rain,” Gage said of making snow in 90 percent humidity. “The atmosphere is just so saturated already, the water molecules won’t freeze.”

Even if the temperature is right, wind can make snow-making inefficient, Gage said.

The portable guns, which use a large fan to blow the snow, do make things easier by automatically calculating the conditions and adjusting the water flow and pressure to match.

“The auto guns are probably my favorite,” Gage said. “They are instant, right there, actually what you are going to be blowing. The weather station (in the towers) on top of Pine is excessively useful, but it is also in a tower 15 feet off the ground.”

But Bachelor has experienced few optimum conditions this year.

On a night with perfect snow-making conditions, Mt. Bachelor’s system can dump 400,000 to 500,000 gallons of water in a single night, Gage said.

This season, the system has been able to drop 50,000 to 60,000 gallons on an average night.

With an inversion already set in, one night this year the snow-making crew stood in the parking lot of the West Village, where it was only 23 degrees.

Four-hundred vertical feet higher, an automated gun read the temperature at 39 degrees, too warm to make snow.

“People might wonder why we haven’t been able to get the snow-making run going when it feels cold in town,” Lomax said. “Much of the cold weather this season so far has come in with an inversion.”

Mt. Bachelor’s snow-making operation is small compared with some of the big-name resorts around the West. Sun Valley, Idaho, for example, uses more than 570 automated guns and makes snow all season.

Bachelor generally only makes it until late December, when there is usually enough natural snow to blanket the mountain.

Still, snow-making is critical in the early part of the skiing and snowboarding season.

“Our snow-making system is basically designed to put down a good layer of durable snow on a really high-traffic run,” Lomax said. “It works well for that. It helps us at the top or the bottom of the lift, where there is extra traffic, and the steeper parts in the middle.”

Once Thunderbird has enough snow, the snow-makers will move to the terrain park, which uses an excessive amount of man-made snow, Lomax said.

In all, Mt. Bachelor uses 5 million to 6 million gallons of water to make snow during one season.

In variable conditions such as those found in Central Oregon, Gage said, Mt. Bachelor has the right system, despite its relatively small size.

With the amount of snow that usually falls in the Cascades, the man-made snow works to enhance the natural stuff.

And a mix of man-made and natural snow makes for better conditions for those runs, Gage said.

“Being able to mix that snow can create a more consistent, longer-lasting surface than just Mother Nature or just man-made (snow),” Gage said. “We can mix a little bit of the natural and get a little softer surface than an area that has a lot of snow-making. Their surface can get really hard, really fast. But a little bit of natural can create a little more fun.”

Ready for the season

• Mt. Bachelor will open this morning, with Pine Marten Express and Sunshine Accelerator chairlifts operating. The ski area has a 16-inch base, according to its Web site.

There will be a small terrain park open near the top of Sunshine, according to Frankie Labbe, a Mt. Bachelor spokeswoman. The ski area will offer reduced ticket prices, depending on available terrain. People should check www.mtbachelor.com for updated ticket prices.

• Hoodoo Mountain Resort has a 14-inch base and could open by Thursday, according to its Web site.

• Willamette Pass, which has a 10-inch base, might also open by Thursday, according to its Web site.