As Hurricane Irene bears down on the East Coast, packing winds of 90 miles per hour, more than two million people have been told to evacuate.
The National Hurricane Center has downgraded Irene to a category one hurricane, but warns it will still be extremely dangerous.
Hurricane specialist Mike Brennan said the hazards remained the same and “the emphasis for this storm is on its size and duration, not necessarily how strong the strongest winds are."
Irene is progressing in a north-easterly direction at 14 miles per hour, and is expected to weaken after hitting the coast of North Carolina on Saturday morning. It will then continue on its path north along the mid-Atlantic coast on Sunday.
The Associated Press reported that tropical storm-force winds were blowing ashore ahead of Irene, with wind and rain knocking out power to about 45,000 homes along the North Carolina coast.
Seven states, from North Carolina to Connecticut, have declared emergencies, while President Barack Obama warned Irene could be an "historic hurricane".
Upon reaching New York City, Irene will likely have turned into a category one hurricane, with USA Today reporting expected high winds and up to 12 inches of rain.
New York Mayor Michael Bloomberg ordered an unprecedented evacuation of more than 300,000 people living in low-lying parts of the city.
We've never done a mandatory evacuation before now and we wouldn't be doing it if we didn't think this storm is going to be serious.
The city has ordered both buses and the subway system to be shut down from noon Saturday. New York City's five main airports will also be shut.
Nearly 100 shelters with a capacity of 71,000 people have been opened.
(Read more on GlobalPost: Hurricane Irene weakens slightly as rains hit US east coast)