U.S. President Barack Obama has declared an emergency for most of the states hit by Hurricane Irene, including North Carolina, Virginia and New York, in order to make federal resources available to support response efforts.

The storm, which is no longer a hurricane, still has winds of 85 kilometers per hour. It moved into Canada early Monday, where 20 centimeters of rain could fall across Nova Scotia and New Brunswick.

Mr. Obama cautioned Americans, “This is not over.” Severe flooding is expected across much of the northeastern U.S.

The storm killed at least 18 people and paralyzed ground and air traffic in its journey up the eastern U.S. coast.

Major airports serving New York are expected to re-open early Monday. Much of New York's subway system is expected to be available for many commuters returning to work Monday.

More than 4 million homes and businesses along the east coast lost electrical power. A Washington area power company dispatched 2,400 people to assist in repair efforts in the region. Some power companies report it may take at least a week to completely restore electrical service.

As the impending storm approached, nuclear power plants were taken offline in Maryland and New Jersey.

As Irene approached Canada late Sunday, Hydro-Quebec reported nearly 250,000 customers near Quebec were in the dark.