FARMINGTON — Town officials are hoping that a winter freeze will help stabilize an eroding riverbank that threatens a portion of Whittier Road.

If the bank of the Sandy River, which has been losing ground since a tropical storm in August 2011, loses three more feet, Public Works Director Denis Castonguay said it could trigger a decision to close the road.

If the ground is not lost before winter’s freezing temperatures set in, Castonguay said the embankment will harden and be less susceptible to forces of erosion.

In preparing for a possible closure, the town is working with the Maine Army National Guard to explore the building of a bypass behind five homes on the roadway.

A $277,000 project to fix the crumbling bank was put on hold over the summer amid concerns from the federal government about a potential negative impact on the endangered Atlantic Salmon, which uses the river as a critical spawning habitat.

Castonguay said that, if the road does last into the winter without being closed, the spring thaw would be a time of heightened concern.