Firefighters in the US state of Arizona have managed to get only 5% of the massive Aspen fire under control.
The terrain makes it difficult for firefighters to tackle the blaze
The wildfire, which began almost a week ago, now covers 11,400 acres in rough terrain which makes firefighting particularly difficult.
It continues to push north, fuelled by winds and warm weather.
It may be weeks before the fire is under control.
"This fire's going to be here for a while and it's going to be very large," said Jeff Whitney deputy commander of the team which is battling the fire.
More than 250 homes have been destroyed so far, mainly in the holiday resorts which dot the area.
The weather is likely to remain hot and dry in the next week, giving little hope that nature will help stem the blaze.
About 1,000 people have been forced to flee their homes, but so far no-one has been seriously hurt in the fire.
An important space observatory escaped serious damage at the weekend despite earlier fears that it could be destroyed in the blaze.
However, three broadcast transmission towers were lost.
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