The Minnesota Vikings and Ramsey County announced an agreement on Tuesday to build a $1 billion football stadium with a retractable roof in Arden Hills, capping a furious day of last-minute negotiations and brushing aside concerns from Gov. Mark Dayton and others that the project may be seriously flawed.

Vikings owner Zygi Wilf, flanked by the team's iconic former coach, Bud Grant, described the deal as purple-clad fans broke into cheers and applause at a county public works facility. The team, trying to build momentum for a plan that already faces heavy skepticism at the State Capitol, showed a film that attempted to link the new stadium to the team's glory days, when it played in the cold at Met Stadium in Bloomington during the 1960s and '70s.

"We believe we have selected the ideal site here in Arden Hills,'' Wilf said. "This establishes a venue for the next generation that our kids and ourselves can be very proud of."

"I'm very happy today. I look to see the future of the Minnesota Vikings in Arden Hills,'' said Ramsey County Commissioner Tony Bennett, who along with fellow Commissioner Rafael Ortega spearheaded the county's efforts to attract the Vikings.

The plan came a day after Minneapolis, seeking to keep the Vikings at the Metrodome site in downtown Minneapolis, announced its own complex plan to use a series of tax increases to build an $895 million stadium and renovate the aging Target Center. But the Vikings reacted tepidly to that proposal.

The Ramsey County site, a former 260-acre munitions plant about 10 miles from downtown St. Paul, is one of the largest swaths of undeveloped land left in the Twin Cities. Wilf plans to build a 1.6 million-square-foot stadium with 21,000 parking spaces and other developments, including a Vikings Hall of Fame. The team would contribute $407 million, or 44 percent. The county, which began its improbable quest for a stadium last summer, would finance $350 million with a half-cent sales tax increase, leaving the state to contribute $300 million.

Major hurdles

Even before the deal was made public, signs erupted that the Ramsey County plan faces high hurdles at the Legislature.

House Speaker Kurt Zellers, R-Maple Grove, said the money needed for road improvements in Arden Hills poses a problem. Rep. Morrie Lanning, R-Moorhead, the stadium plan's chief House author, said he would not move a stadium bill until road issues were resolved. To do otherwise, he said, was "asking for trouble."

Legislators have only 12 days left before they must adjourn the session, and many were voicing concerns on Tuesday that stadium negotiations have become so complex they might miss the deadline.

As reports swirled through the State Capitol early Tuesday that the Vikings and Ramsey County had reached an agreement, Dayton launched what would be a whirlwind day of stadium politics by splashing the Arden Hills project with his own dose of reality.

In a surprise morning news conference, he said the state's share was fixed at $300 million, whatever the cost of the new roads needed. State transportation officials estimated that a stadium without surrounding development would require $175 million in roadwork, while a fully developed site would need up to $240 million.

"I'll support either project up to $300 million," Dayton said of the competing Arden Hills and Minneapolis plans.

Hours before the Arden Hills deal was announced, Ted Mondale, the governor's chief stadium negotiator, issued a long-awaited cost comparison of the two sites that showed the Arden Hills stadium would cost up to $1.28 billion, compared to $895 million at the Metrodome. According to the analysis, the Arden Hills site would require $275 million to $340 million in highway, parking and other improvements. The Metrodome site would need $30 million for new parking spaces and skyway connections.

That quickly brought charges that there was back-room maneuvering taking place to try to steer the project back to Minneapolis. Rep. Michael Beard, the Republican chair of the House transportation panel, said he was concerned about growing "bias" in favor of Minneapolis.

"It sounds like the Vikings have already picked their prom date," he said, referring to Arden Hills. "If that's the case, then, I guess we've got to figure out how to get them to the prom."

Business weighs in

Charlie Weaver, the executive director of the Minnesota Business Partnership who has played a major behind-the-scenes role with the project, said that influential Twin Cities business leaders -- including U.S. Bancorp chief executive Richard Davis, Ecolab chief executive Doug Baker and Ken Powell, the chief executive of General Mills -- have been cautioning the Vikings about the additional costs in building in Arden Hills.

Sen. Julie Rosen, R-Fairmont, the stadium plan's chief Senate author, said the Vikings asked whether the state could contribute $300 million plus road improvements. Rosen's one-word answer: "No."