Workers shovel snow off the roof of Mall of America Field at the Hubert H. Humphrey Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Workers shovel snow off the roof of Mall of America Field at the Hubert H. Humphrey Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants.(AP Photo/Ann Heisenfelt)

The collapsed roof of the Metrodome can be seen with the skyline behind in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Workers shovel snow off the roof of Mall of America Field at the Hubert H. Humphrey Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Snow falls into the field from a hole in the collapsed roof of the Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Snow falls into the field from a hole in the collapsed roof of the Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Snow falls into the field from a hole in the collapsed roof of the Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Snow falls into the field from a hole in the collapsed roof of the Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Snow has fallen through a hole in the roof of the Metrodome and can be seen on the field in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Snow falls into the field from a hole in the collapsed roof of the Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Snow falls into the field from a hole in the collapsed roof of the Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches (43 cms) on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Workers shovel snow off the collapsed roof of Metrodome in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm in Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

The collapsed roof of the Metrodome is shown in this aerial view in Minneapolis on Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)

Holes in the collapsed Metrodome roof can be seen in Minneapolis Sunday, Dec. 12, 2010. The inflatable roof of the Metrodome collapsed Sunday after a snowstorm that dumped 17 inches on Minneapolis. No one was hurt, but the roof failure sent the NFL scrambling to find a new venue for the Vikings' game against the New York Giants. (AP Photo/Ann Heisenfelt)