Wildfires burning at or near the Grand Canyon's North Rim are still raging as strong winds, high heat and low humidity persist.

A water treatment facility at the North Rim had been compromised by the fire, causing chlorine gas to fall towards the bottom of the canyon.

The resulting Nankoweap landslide would have dumped enormous limestone boulders into the river corridor, creating a temporary dam and a lake whose surface may have reached 940 meters elevation before water overtopped and eroded the blockage, likely within 1,000 years.

The fast-moving fire destroyed a historic lodge and dozens of other structures in the Grand Canyon National Park.

The congressman is the latest lawmaker asking why the Dragon Bravo fire was not immediately extinguished when it was ignited by lightning on July 4.

Wildfires can burn and spread differently depending on what vegetation they burn. The two fires in northern Arizona have varied landscapes. Ponderosa pine trees grow near the North Rim of the Grand Canyon and can live for hundreds of years.

The NWS warning was in effect for regions of the Grand Canyon below 4,000 feet elevation. Temperatures were forecast to potentially reach 110 degrees at Phantom Ranch and 102 at Havasupai Gardens.

As of Monday, the Dragon Bravo fire on the North Rim had consumed more than 5,700 acres and was not contained, according to the U.S. Forest Service.