The Nashwaak River in New Brunswick is one of the rivers that's already reached the flood stage - even before the rain and snow that's coming.

Residents around Durham Bridge, N.B., have been eager to see the ice jams in the river.

Late Monday evening, New Brunswick's Emergency Measures Organization put out an alert that, because of ice jams, the water level is much higher than usual and in flood stage.

“(An) ice jam is where ice has accumulated and is no longer flowing down the river, and the water in the river is finding a way,” said Geoff Downey of New Brunswick’s EMO. “It's a bottleneck, essentially.”

It’s a bottleneck that can cause the river to rise quickly.

“You don't know where they're going to form, when they're going to form, and when they're going to break up as well,” Downey said. “It's the unpredictable nature that makes it a particular danger.”

The EMO says the Nashwaak River can only jam in certain places, and one of those spots is Durham Bridge. Over the course of a few hours Tuesday, the ice jams have moved southward down Nashwaak River to the point where they are now fully blocking the flow of the river at Durham Bridge.

The flooding and the ice jams are drawing quite a crowd around here.

Edward Bailey has come here to watch the river melting for the past 80 years.

“It's just a great big bunch of ice,” Bailey said. “It stops, and if you go up the river a ways, you can see it's still coming down. So it's quite fascinating.”

Donald Hovey stopped to see them on his trip from Porter Cove to Fredericton where he lives.

“The ice is starting to move a bit around the bridge in Ludlow,” Hovey said. “Not massive but it's starting.”

Dave Gorman lives along the river in Durham Bridge and spent the day taking in the movement of the shifting ice.

“There's quite a bit of ice there, but if the ice comes down from the upper lake, it will push that all right though and it can cause havoc down around here,” Gorman said.

Closer to the end of the day, EMO told CTV News that the river level dropped to 21 metres -- just at flood stage.

Still, residents know this is just the beginning. It will get worse as it warms up and the ice shifts, melts and moves.

“So if that comes down, it could make things pretty interesting,” said Gorham.

Said Hovey: “It's early yet - we're still going to get more.”

The water level doesn't have too far to go before it's at street level, and there's quite a bit of ice on the Nashwaak River that still needs to melt.

With files from CTV Atlantic’s Jessica Ng.