Glacier National Park officials planned to proactively close the alpine section of Going-to-the-Sun Road on Wednesday night as a potent rainstorm was expected to swamp the Northern Rockies.

The closure was anticipated to last through early morning Friday due to forecasted heavy rain and thunderstorms that could set off mudslides and falling rock.

Park officials said that the road will be closed between Avalanche Creek and Jackson Glacier Overlook. 

Heavy rain at rates of half an inch per hour was predicted for the park, where up to 2 inches of precipitation was possible. New or existing burn scars could be susceptible to debris flows. 

High elevation snow was also in the forecast above 6,500 feet for Glacier Park, according to the National Weather Service in Missoula. A winter weather advisory was issued for West Glacier from noon Thursday through Friday morning. 

Glacier’s mountain terrain will see highs in the 40s and lows in the 30s on Thursday and Friday.

“If you have backcountry plans ... please plan for wet and cold conditions,” the Weather Service warned Wednesday.

Visitors to Glacier Park should check the weather forecast and park road status.