(KPAX) GLACIER NATIONAL PARK – It’s a sure sign of spring — plowing in Glacier National park began Wednesday as crews work to open Going-to-the-Sun Road for the summer.

Park spokeswoman Lauren Alley says it takes plow crews about three months to plow up to Logan Pass and install hundreds of guard rails.

This year, pavement preservation will follow behind plows, since paving can’t happen until the roads are clear of snow.

There is no ski, snowshoe, hiking, or bicycle access beyond Lake McDonald Lodge while crews are working.

Hiker and biker access is open to Rising Sun on the east side of the road

With millions of visitors every year, preservation techniques will help maintain the heavily traveled roads.

However, Alley says April and May weather can bring some challenges to crews.

“If it’s a really warm day they’ve got to come down because there is too high of avalanche danger for them to work,” she explained.

“On the other hand, we could get a blizzard and that would also dump a lot of snow up there and they’d have to go back and redo some work,” Alley added.

She added that Going-to-the-Sun Road will not be open before June 21. The famed road opened last year on June 23.