The surest sign of spring in Glacier National Park isn’t the long sweet note of the varied thrush or the call of swans sweeping over the Continental Divide — it’s the rumble of diesels and the screech of steel digging into a winter’s worth of snow.

Park plow crews hit the pavement April 1, starting with the Camas Road on the west side. When that’s completed, they’ll start work on the Going-to-the-Sun Road, Park spokeswoman Denise Germann said.

On the east side, plow crews began work on the Chief Mountain Road. They will move on to the St. Mary, Many Glacier and Two Medicine areas next before heading up the Sun Road.

It usually takes Park crews about two and a half months to clear the Sun Road. This will be the first summer in years without construction work taking place on the west side, so the road will open to Logan Pass for motor vehicles when it’s safe and clear of snow, Germann said.

Plow crews have their work cut out for them. This year’s snowpack is running about 128 percent of average for the Flathead River Basin, with higher amounts locally, according to the Natural Resource Conservation Service. Spring weather will have an impact as snow continues to fall in the Park’s lower elevations.

On the east side, construction on the Sun Road will continue from Siyeh Bend to Rising Sun. The earliest the Sun Road will open to motor vehicles on the east side is June 20, Germann said.

Last year, the Sun Road opened to Logan Pass from the east side on June 15. Road construction delayed a west side opening until June 21.

For plowing updates, visit online at http://home.nps.gov/applications/glac/roadstatus/roadstatus.cfm.