A builder’s halfpipe dream comes true

As soon as Steve Petrie arrived at Cypress Mountain, high above the city, a hint of panic set in.

It was early January, and Petrie needed a whole lot of snow to build a halfpipe for the Vancouver Olympics snowboard competition.

All he got was rain.

“It rained and rained and rained,” he recalled. “We were watching all the snow melt away.”

Which makes the last two nights semi-miraculous. After weeks of fretting -- not to mention complaints from riders -- Petrie’s creation produced stirring performances in both the men’s and women’s finals.

“The first two days of practice were some of the worst pipes we’ve ridden all year,” said bronze medalist Scott Lago of the U.S. “Then, overnight, it went to one of the better ones.”

This transformation qualifies as a great achievement -- and relief -- for a halfpipe guru from British Columbia who has spent 16 years building competition sites around the world.

“The most challenging conditions I’ve ever faced,” Petrie said.

His job starts with “summer dirt work,” an excavator showing up months in advance to create the approximate shape of a 22-foot pipe. When winter arrives, workers pack snow onto this earthen mold using a snow cat and a laser level to keep the walls even.

Then comes another snow cat with a giant auger to carve the exact shape. Builders keep the pipe a little narrow so they can whittle away, making small adjustments, as the competition approaches.

Finally, a sprinkling of salt or fertilizer helps to harden the surface. At least, that’s how it is supposed to work.

In Vancouver, Petrie and his crew spent most of January and early February making snow to keep up with all that was lost in the rain.

There wasn’t enough white stuff left to form a drop-in ramp, so they had to build scaffolding on a dirt mound, pack it with hay bales and blow snow over this makeshift structure.

None of which left time for test rides or fine-tuning.

“Usually,” Petrie said, “pipes need to mature.”

As the athletes arrived, Mother Nature threw a final curve. The weather dried out, which should have been helpful, except the temperature remained warm.

“We ended up with this really funky snow that was difficult to form,” Petrie said. “The wall shape was good, but the middle of the pipe was dry so it turned almost to sugar.”

As in soft and granular, wrecking havoc on riders.

“It was just too soft,” said Britain’s Lesley McKenna. “I keep sinking into the wall.”

And, as Petrie recalled, snowboarders “don’t mind telling you when they think something’s not right.”

Oddly enough, a final burst of rain came to the rescue, adding just enough moisture so that Petrie could make everything right.

That meant dropping a rope down the vert line, using chain saws to rough-shape the lip, then bringing the cats back for polishing.

The final result wasn’t perfect -- still a little sugary, the surface a little thin on the walls -- but riders showed their appreciation to Petrie and his crew.

Not that Petrie had to be told. He already knew from all the spinning, flipping tricks and the “Double McTwist” that Shaun White stuck to win gold.

“To see them ride like they did,” Petrie said, “you know you did your job.”

david.wharton @latimes.com