Officials were trying to pinpoint the cause of the breakdown and to discover how it cascaded so quickly through much of the northeastern United States and the Canadian province of Ontario, affecting tens of millions of people in New York, Detroit, Cleveland, Ottawa, Toronto and a host of smaller cities.

 

In Washington, the House of Representatives Energy and Commerce Committee said it would hold an investigation into the blackout.

   

Almost 24 hours after the breakdown, authorities predicted that power would likely be restored by the end of the day to most customers.

 

Detection

   

"Right now we think the vast majority of customers without electricity will be restored by end of day," said Michehl Gent, head of the North American Electric Reliability Council.

   

Gent said the entire "event" was first detected on lines in the Midwest and lasted no more than nine or 10 seconds, cascading through the power system.

   

As people digested the speed with which the electricity system collapsed, they also expressed relief that the blackout was not the result of an attack.

   

People lost their moorings
in the blackout

Emergency procedures designed to evacuate people from subways and elevators worked. People took the inconvenience with good humour and law and order prevailed in most placed.

   

Police in Ottawa reported some looting and also attributed two deaths to the outage. New York City reported only one death.

   

The recovery was far from smooth. Air Canada cancelled all flights worldwide after emergency power systems crashed at its main operations control centre near Toronto, stranding thousands of passengers.    

 

Difficulties 

   

Telephone systems slowly began returning to normal but there were still difficulties, particularly on wireless networks. Banks worked to reopen branches and automatic teller machines.

   

Bush, visiting California, praised the country's emergency response system, saying work since the September 11 attacks to upgrade procedures had paid off. Now, the nation needed to make the same investment in its electricity grid.

   

"I view it as a wake-up call," Bush told reporters, adding that the blackout was "an indication we need to modernize the electricity grid."

 

"We're a superpower with a third-world grid. We need a new grid."

--Bill Richardson, former energy secretary

New York Governor George Pataki said he wanted to know why the system crashed so catastrophically.

   

"How did this happen, why did it happen and why did we have a systemic failure across the power grid in the northeast when we were told after the blackout in the 1960s that this would not happen again?" Pataki said.

   

Procedures put in place after a huge blackout in 1965 to isolate breakdowns to small areas failed.

   

Former Energy Secretary Bill Richardson said much of the US electricity system was 50 or 60 years old. "We're a superpower with a third-world grid. We need a new grid," said Richardson, now governor of New Mexico.