https://www.thedenverchannel.com/li...le-high-stadium-where-the-denver-broncos-play
Secret No. 6: There are 2 tarps for the field.
There's the snow tarp, the thick one, created to keep moisture out.
There's also a grow tarp that allows the sun in, but keeps the frost out.
The grass at Sports Authority Field is 100 percent Kentucky Blue Grass that grows year round. It's not allowed to go dormant, DeWitt said.
Under the grass is 21 miles of heated pipes to help keep the grass green year round.
Sports Authority Field is one of the few stadium to have a flat playing surface. That's because that underground piping system also has a vacuum system that can drain the field of water during rain and snow storms.