A Black Stream Of 'Goo' Ripped Through This River Park In Tucson Again (VIDEO)
What is that!?

It's monsoon and wildfire season in the desert—which can cause a combination of deadly flash floods and debris flows.
A Tucson post-fire debris flow was captured on video, and Pima County shared the unusual recording to its Twitter page.
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Pima County explains that these occurrences are common after an area has been scorched, and the rushing water "causes large amounts of burned material."
The black "gooey" stream is a combination of ash, sand, silt, rocks, and trees.
With thunderstorms and showers on the forecast for parts of Arizona, flash floods continue to be a threat as "there is sometimes little to no warning of impending flash floods or debris flows."