Cars sit idle on flooded streets in downtown New Orleans after Hurricane Katrina came ashore on Monday

Hurricane Katrina continues to dump torrential rains on the U.S. Gulf Coast after coming ashore with winds exceeding 200 kilometers an hour. Flooding and damage appears extensive in affected regions, but the full extent of the devastation, including loss of life, is not yet known.

Katrina came ashore just east of New Orleans, Louisiana and continued northward, into the state of Mississippi. The hurricane tore roofs from buildings, including a section of roof at New Orleans' massive domed stadium, where many people had taken refuge. The winds blew out windows, and downed trees and powerlines. Extensive flooding and massive power outages are reported from New Orleans to parts of Alabama.

Speaking in Arizona, President Bush said those affected by the storm will not be abandoned. "Our Gulf Coast is getting hit, and hit hard. I want the folks there on the Gulf Coast to know that the federal government is prepared to help you when the storm passes," he said. "In the meantime, America will pray, pray for the health and safety of all our citizens."

Federal emergency officials say they have disaster-response teams in place around affected areas and will mobilize and begin work as soon as local conditions permit.

Since coming ashore the storm has lost much of its power but officials say there is still potential for additional flooding.