Although the bulbous white roof of the Metrodome is set to be deflated Saturday, the exact timing of the controlled collapse all depends on Minnesota’s ever-fickle weather.

If winds swirl more than 5 miles per hour, the deflation could very well be delayed, said Michele Kelm-Helgen, chairwoman of the Minnesota Sports Facilities Authority, the public body overseeing construction of the new $1 billion Vikings stadium.

High winds could cause a safety hazard, as the roof encompasses about 10 acres of Teflon-coated fiberglass fabric, authority officials said. Combined with the steel cables that hold up the roof, the entire top portion of the Dome weighs close to 300 tons.

Given that a snowstorm and a winter-weather advisory were predicted for early Saturday morning by the National Weather Service, it was unclear whether the scheduled deflation would actually occur. If the weather does cooperate, the event likely will occur earlier in the day, though the authority did not release an exact time.

The authority also discouraged onlookers from hovering about the stadium’s environs in anticipation of the deflation.

“This is a construction site, and there are many safety issues,” Kelm-Helgen said, noting that a Saturday was chosen because there are fewer people downtown on the weekend.

Construction of the new stadium, which will be located roughly where the Dome stands in downtown Minneapolis, has already begun with the excavation of a giant crater on the eastern stretch of the property to make way for the new structure’s pilings. The Vikings played their final game in the Dome on Dec. 29, so stadium officials need to deflate the roof to prepare for the 31-year-old structure’s demolition piece by piece, beginning next week.

First the relief vents in the Dome will be opened, then the fans that support the roof will be turned off and the roof will come down slowly. The entire process is expected to take 20 to 40 minutes, and it will be captured from cameras inside and outside the Dome for

The fabric will be recycled by St. Paul-based excavator Frattalone Companies, which will cut it up and use it for future construction projects. Already the turf and most of the bright-blue seats have been removed, leaving a kind of concrete shell inside the stadium.

“This is a new era for the Minnesota Vikings, with a new stadium and a great new coach,” said team spokesman Lester Bagley. “This will be a milestone, a very visible symbol of what’s to come when the roof comes down. It’s been a long time coming.”

Waiting for high court

Meanwhile, there was no word Friday from the Minnesota Supreme Court regarding a last-minute legal challenge filed by three Minneapolis residents over the constitutionality of the state bond sale to help pay for the stadium. The state halted the sale of $468 million in bonds earlier in the week.

Kelm-Helgen said she thinks the Supreme Court justices understand the authority’s need to quickly resolve the issue.

“We need to get the court case resolved so we can have confidence moving forward,” she said.