A neighbor told KGW-TV that he and other neighbors were able to rescue the woman who was alone in the house by rigging an extension ladder to the rooftop.
"She's muddy, but no, she's fine," the neighbor told the Portland television station.
Power was out in the hilly southwest Portland neighborhood, and fire crews were at the scene with city workers to assess the damage and determine what caused the house to break away.
Lieutenant Rich Tyler of the Portland Fire Bureau told KGW-TV that it was the first time he had ever seen a house slide off its foundation.
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