Two ice-breaking tugs were on the Kennebec River on Tuesday ahead of a larger vessel later this week, a U.S. Coast Guard official said.

The unusual midwinter effort comes more than a week after a sudden ice jam caused destructive flooding in low-lying areas in Augusta and Hallowell.

Lt. Matthew Odom, chief of the Coast Guard’s Waterways Management Division in Northern New England, said two 65-foot-long icebreakers are gauging the conditions before another 65-foot-long vessel and a 140-foot-long icebreaker join the operation this week.

As of 11 a.m. Tuesday, the Kennebec River in Augusta was still below 10 feet — flood stage is 12 feet — and it has slowly risen since Monday.

The Augusta Police Department said Front Street remains closed. The rain may cause the ice jam to move, which could help break up the jam in Farmingdale or raise the river level behind the jam, which would cause flooding in Augusta and Hallowell.

A U.S. Coast Guard icebreaker slices through the Kennebec River in March 2007 in Gardiner. Maine Emergency Management Officials said a Coast Guard icebreaker will be brought up the river to reduce the risk of upstream ice jams, which have caused midwinter flooding in Augusta and Hallowell. (Kennebec Journal file photo)