Guided by experts from Sunday River and Sugarloaf ski resorts, crews build the scaffolding for a terrain park in Monument Square on Wednesday in preparation for the Downtown Showdown to be held from 5:30 to 7 p.m. Friday.

After 6 to 8 inches of snow is packed onto the structure, more than two dozen athletes will compete in snowboarding and ski events.

Friday’s free event will be followed by the daylong WinterRush Festival on Saturday, with outdoor events for the whole family.