If you're planning a trip to Yellowstone National Park next month, you'll want to read this update about road work that will cause some snarls for visitors. 

Park officials say two sections of the Grand Loop Road will be closed due to construction after the Labor Day holiday weekend, and that travel between some points "will involve long detours and significantly longer than normal travel times."

* The road linking Old Faithful with West Thumb and Grant Village will be closed for the season starting 6 a.m. Tuesday, Sept. 2, so the bridge at Isa Lake can be removed and replaced. 

This road closure will require visitors traveling between the South Entrance and Old Faithful or West Yellowstone to detour through Fishing Bridge Junction and Canyon, increasing the travel time by approximately two hours. Despite the closure, visitors will still be able to drive south from Old Faithful as far as the trailhead to Lone Star Geyser and north from West Thumb Junction to access the DeLacy Creek trailhead.  

* The road from Mammoth Hot Springs to Norris will be closed due to construction from 11 p.m. Sunday, Sept. 14, until 7 a.m. Tuesday, Sept. 30.  

During this closure, travel between Mammoth Hot Springs and Norris will require a detour through Tower Junction and Canyon, a drive of approximately 90 minutes.  Visitors traveling between Mammoth Hot Springs and West Yellowstone should plan on the trip taking approximately two and a half hours. 

Visitors will still be able to access the road to Sheepeater Cliff from the north and Norris Campground from the south during this two week road closure. Indian Creek Campground closes for the season on Sept. 8, before this road closure goes into effect. 

Before and after the full closure, expect construction delays of up to 30 minutes on this road segment.  This section of road will also be closed nightly between 11 p.m. and 7 a.m. prior to the Sept. 14 full closure, except over the holiday weekend.

There is one ongoing road project immediately outside the park’s North Entrance.  Travelers can expect 24-hour access with brief delays on a short section of US-89 through Gardiner, Mont., starting Monday, Sept. 1.  

With careful planning, those traveling from North to South or East to West through Yellowstone should experience limited impacts to their travel times. Travelers are encouraged to consult the Official Park Map to plan their travel around the road closures.  The map is distributed to visitors at park entrance stations and is also available online at http://go.usa.gov/Phw4.  Detailed road information is available 24 hours a day online at http://go.usa.gov/PhAH or by calling 307-344-2117.