At least three people have been killed as a massive storm brings power outages, flood watches and flight delays to the US East Coast.

A woman died in floodwaters outside Charleston, South Carolina, and two men in north-eastern states were killed as the storm moved toward Canada.

Millions of East Coast residents were on flood watch and over 700,000 were without power earlier on Monday.

Lingering until Tuesday, the storm is expected to snarl up holiday travel.

The weather brought widespread heavy rain that led to river flooding and flash flooding, the US National Weather Service said. Some areas were “experiencing road washouts”.

The first storm-related death was confirmed in Mount Pleasant, South Carolina. Nancy Morrow, 72, was killed after she got stuck in a vehicle submerged under water, officials said. Officers jumped in the water to try to save her.

In Hanover, Massachusetts, on Monday, an 89-year-old man, Robert Horky, died after strong winds knocked a tree over on to his trailer, causing severe head trauma, local officials said.

A third person, whom police have not yet identified, died in Windham, Maine. A tree fell on him while he was trying to clean debris from his roof, authorities said.

Heavy winds and rain have made for dangerous travel conditions, leading to over 3,400 delayed and 500 cancelled flights travelling to or in the US, according to FlightAware. The worst airport impacts were in the Boston and New York areas.

Schools across all of the New England region have also been forced to cancel or delay classes because of road conditions.

The storm has had a number of effects on several states along the East Coast:

The weather comes nearly a year after a major winter storm in the US caused travel chaos during the holiday travel season.