At least 100 structures have been damaged or destroyed, mostly in the Rist Canyon area as the High Park Fire continues to spread in Colorado. Officials say that some structures may have been damaged in other areas including Poudre Park, Soldier Canyon and Mill Canyon.

At the latest briefing Monday afternoon, officials did say the cause has been determined to be lightning. The High Park Fire is still estimated to be about 36,930 acres and continues to grow.