Officials have declared states of emergency in parts of southwestern Nova Scotia after the region was hammered by heavy rains over several days that flooded homes, roads and farmland.

Local states of emergency were extended Monday night to parts of Barrington, Yarmouth and Argyle due to flooding and damage from more than 200 millimetres of rain that has fallen on the region since Friday.

Nova Scotia's Emergency Management Office said damage to bridges, as well as local road closures in those areas, have led to the removal of 120 families from their homes.

Officials are also closely monitoring the Lake Vaughn Dam, the Carleton Dam and the Gardner Mills Dam as water levels rise.

"Officials continue to be on top of the situation and are doing everything they can to help ensure the safety of residents," said Ramona Jennex, Minister for Emergency Management.

More than a dozen roads in the region have been closed or washed out, but that figure could rise as water levels peak over the next two days.

As of late Monday morning, the Emergency Management Office reported 29 road closures in Colchester, Cumberland, Kings, Lunenberg, Queens, Shelburne and Yarmouth Counties. More than half of the closures were in Yarmouth County.

The heavy rainfall has overwhelmed a spillway in Raynardton, N.S., leaving officials unable to control the flow of water, said Harold Richardson of the District of Yarmouth.

Raynardton is located about 20 kilometres northeast of Yarmouth.

Because the local dam may give way, people living in Raynardton are being told to leave the area. Richardson said those who choose to stay in their homes could become stranded as roads and bridges are being closed in the area.

Emergency management officials warn that waterways that appear calm can quickly become dangerous, as water levels -- and how fast the water is flowing -- change without warning.

"Moving water only 15 centimetres deep can cause people to be swept off their feet," according to a statement from the Emergency Management Office.

Drivers are being advised to be cautious and to watch out for large amounts of water on the road.

Meanwhile, parts of New Brunswick have received three months' worth of rain in just a few days. More than 300 millimetres of rain have fallen in some areas, including Mechanic Settlement, breaking a local rainfall record.

In Moncton, more than 110 millimetres of rain combined with high tide Sunday night to cause widespread flooding throughout the city.

High winds and choppy waters from the stormy weather have also delayed the start of lobster season. Hundreds of boats that were scheduled to head out to the Bay of Fundy on Monday remained near shore.

The Department of Fisheries and Oceans has also closed large parts of the Bay of Fundy shoreline to clam digging and oyster harvesting over concerns that runoff from heavy rain can increase the risk of contamination.

While the rain is tapering off over Nova Scotia, between 10 and 15 millimetres more is expected to fall on western New Brunswick overnight and into Tuesday before the sun comes out on Wednesday.

With files from The Canadian Press and reports from CTV Atlantic's Kelland Sundahl and Mike Cameron