Tracking Sandy day by day:

Oct. 22: Tropical Depression 18 forms over the southwestern Caribbean, about 515 kilometers south-southwest of Kingston, Jamaica. Six hours later, the U.S. National Hurricane Center says it has grown to tropical storm force and names it Sandy.

Oct. 23: Jamaica and Cuba begin making preparations for the strengthening storm.

Oct. 24: Sandy becomes a hurricane with winds of 130 km/h just before slamming into Jamaica west of the capital, Kingston, at about 3 p.m. EDT. The fast-moving storm crosses the island within five hours, killing one person, blowing off roofs and cutting power to half the country.

Oct. 25: Sandy grows into a Category 2 hurricane with winds of 185 km/h and blasts across eastern Cuba in less than seven hours. The greatest damage is in nearby Haiti, where at least 26 people die over two days. By early afternoon, the hurricane rolls into the Bahamas and begins to weaken as winds fall to 150 km/h.

Oct. 26: Sandy's center emerges from Bahamas after killing at least one person and causing widespread power outages. It weakens to winds of 120 km/h. A Puerto Rico man dies in a river swollen by the storm's rains. Forecasters say it is likely to hit the U.S. Eastern Seaboard as a tropical storm early Tuesday.

Oct. 27:  Sandy follows an ominous path along the American east coast -- and threatens to become the first hurricane to deliver a direct hit on Delaware. Officials warn the megastorm could hit the mid-Atlantic states with devastating flooding and massive power outages that could last for days.

Oct. 28:  Authorities order mass evacuations and airlines cancel transatlantic flights as Sandy bears down on the U.S. east coast.

Oct. 29: Hurricane Sandy picks up speed and strength and hits the U.S. eastern seaboard early Monday evening, hours sooner than previously expected.

Oct. 30: U.S. President Barack Obama declares New York and Long Island a “major” disaster area, as the U.S. death toll from superstorm Sandy increased to 39, including many killed by falling trees. As of midday, Sandy's sustained winds were already diminishing from the 130 km/h it was packing at landfall near Atlantic City, N.J. on Monday. But forecasters warn the storm system will continue to effect a region stretching from the U.S. eastern seaboard north to Canada, and as far west as Wisconsin and Illinois, as it churns across Pennsylvania before veering into western New York state sometime Wednesday.

With files from The Associated Press