After Labor Day, road crews will begin work on two sections of Yellowstone's Grand Loop Road (shown in yellow on the map above).
Part of the road between Old Faithful and West Thumb will be closed for the season starting at 6 a.m. on Tuesday September 2nd. They will be demolishing and building a new bridge at Isa Lake. This will mostly affect visitors entering the park from the south entrance on the way to Old Faithful. They should expect an extra two hours of travel time by detouring through Fishing Bridge, Canyon Village, Norris, and finally Madison.
The road from Mammoth Hot Springs to Norris has been under construction with traffic delays all summer of 2014. Note that it will be closed completely from Sunday, September 14th to Tuesday, September 30th. This is to repair road damage from the nearby geysers and hot springs. Within the next five years, the Park Service plans to relocate this part of Grand Loop Road that takes visitors past Frying Pan Spring. During the closure, you will still have access to Sheepeater Cliff south of Mammoth, and Norris Campground north of Norris.
For more information, visit www.nps.gov/yell/parknews/14057.htm