Matanuska River undercuts Glenn Highway, prompting partial closure

PALMER — The Glenn Highway is partially closed near Sutton after the Matanuska River undercut the roadway near Sutton on Saturday, eating into the asphalt surface and prompting emergency repairs.

The river is threatening the highway in the area of Mile 63, according to an alert on the 511 state traveler information site. The Matanuska is running high, swollen with snowmelt from the recent warm weather.

Crews worked through Saturday night placing material to shore up the eroding section of road at Mile 63.4 north of Sutton, according to an update. Flaggers were letting vehicles through and the road was open to one lane. They said immediate plans included a temporary ramp, road widening and a new traffic pattern.

The rate of erosion increased “significantly” Saturday, the Alaska Department of Transportation and Public Facilities said in the update. “Pavement remains intact but we are concerned with the river undercutting the roadway.”

Local residents last week reported major, fast-moving changes to the bank as the Matanuska swallowed about 40 feet of ground in a month — and then kept going. Some expressed concerns that the state wasn’t acting quickly enough to protect the Glenn before this kind of emergency repair would be necessary.

A state transportation official on Friday said the highway “was not likely to be impacted any time soon.” Emergency work was planned to start this week on one immediately threatened section near Mile 76 but the section now experiencing damage was scheduled for a more conventional repair project in coming weeks.

On Saturday, residents reported major and concerning changes as the river consumed large amounts of its banks at the section between Mile 63 and Mile 64.

The highway is busy in summer with visitor and local traffic. It runs east-west, connecting Anchorage and Mat-Su with Glennallen before ending at the Richardson Highway which connects drivers to the Alaska Highway and Canada.

The Matanuska, an unpredictable glacial river, has consumed riverfront property from Sutton to Butte, occasionally swallowing entire homes or outbuildings. Buyouts and home relocations have occurred for decades as government agencies try to move people away from the river.