PORTSMOUTH, R.I. (WPRI) — The search is on for a woman who fell off of the Prudence Island ferry and into the water Monday evening.

Bristol Fire Chief Michael DeMello tells 12 News the woman went overboard around 6 p.m. and several people on the boat saw it happen.

The U.S. Coast Guard plans to search the waters between Prudence Island and Hog Island throughout the night.

DeMello described the current water temperature as “hypothermic,” and didn’t specify whether the woman was wearing a life jacket.

It’s unclear at this time what caused the woman to fall off the ferry.