What you need to know:

• Ice dams on the Matanuska River triggered flooding near the Old Glenn Highway in Butte, creeping within feet of the roadway over the weekend before starting to reced on Monday.
• The Alaska Department of Transportation is actively monitoring the situation, officials said. While some summer flooding along the area is common, winter flooding is rare, borough officials said.
• A stretch of highway near Sutton that was eroded by the river earlier this year was fully repaired in November, state officials said.

BUTTE — State officials are monitoring the Matanuska River water level in Butte after flooding triggered by ice dams on the river crept within feet of the roadway over the weekend.

Water from the river flooded a low-lying area along the Old Glenn Highway at Mile 14.4, near Maud Road, encroaching a roadside bike path over the weekend before starting to recede on Monday, officials said.

The water remained over the bike path Tuesday morning.

State crews first began monitoring the area Friday, according to Justin Shelby, a spokesperson for the Alaska Department of Transportation.

“They’re keeping a close eye on it,” Shelby said.

The state oversees maintenance of the Old Glenn and Glenn highways, including repairs of any erosion caused by the Matanuska River.

While river water often creeps into low spots along that stretch of road when the river volume is high during the summer, winter flooding in the area is rare, said Mike Campfield, a project engineer for the Matanuska-Susitna Borough.

Campfield said the borough had not been alerted to any recent issues.

If the flooding causes erosion on the roadway, state officials will likely close one lane to make repairs, Shelby said. The extent and timing of that work will depend on the type and severity of the damage, he said.

The Matanuska River has long threatened roadways and properties along the highways.

Last month, state crews completed repairs to a section of the Glenn Highway at Mile 63 near Sutton after the river undercut the roadway in June, sending asphalt crumbling into the water. In Butte, six riverfront homes were demolished in 2021 as part of a federal buyout program to prevent structures from falling into the river.

-- Contact Amy Bushatz at abushatz@matsusentinel.com