River of Black Sludge
The dumpster fire that is 2020 has brought us wildfires in Australia, the COVID-19 pandemic, and murder hornets. And now, a river of black sludge is oozing through Arizona. What is going on? (1)
Officials from Pima County tweeted a 53-second video of the black sludge careening its way along a trail on July 16, 2020. They aptly captioned the video, “Who had this on their 2020 hellscape bingo card?” (1)
Who had this on their 2020 hellscape bingo card? pic.twitter.com/fUNvIVS7aw
— Official Pima County (@pimaarizona) July 16, 2020
Pima County’s Facebook page provided a bit more information on the phenomenon. In a post from the same day, officials identified the black sludge as a flash flood. In this context, it seems clear that the apocalyptic-looking river is in fact a mix of water and charred debris. As the flood gets closer to the camera, you can see steam rising off of it. (2)
In the Facebook post, officials said that the video was taken on Wednesday, July 15, 2020 in the Cañada del Oro Wash. They wrote that the flood occurred after a minor storm and added the hashtag #floodsfollowfires. (2)
“Floods can happen anywhere and at any time. But did you know wildfires increase flood risks? It’s true,” Pima County officials wrote on Facebook. “Wildfires like the Bighorn Fire leave the ground charred, barren, and unable to absorb water. Even a light rain can produce devastating flash floods and mudflows, often with little warning.” (2)
Bighorn Fire
The Bighorn Fire started in the Catalina Mountains west of Tucson on June 5, 2020. Thought to have been caused by a lightning strike, the fire burned 119,978 acres before becoming fully contained on July 23, 2020. (3)
Weather conditions at the time of the fire were both dry and windy. This pushed the fire toward communities, and many residents were forced to evacuate. (3)
While the fire has been contained, officials warn that there are still risks associated with the burned area, which is still closed to the public. On a website sharing information about the Bighorn Fire, officials wrote, “While the fire is 100% contained, residual heat within the containment line may be visible for some time. A closure order remains in effect for public safety as there are hazards in the burn scar and the Bighorn Fire increased the possibility of flooding downstream and of sediment and debris runoff.” (3)
Floods Follow Fires
So although residents of Pima County are undoubtedly relieved that the Bighorn Fire has been contained, they still need to worry about flash floods. Pima County’s Floods Follow Fires website warns residents, “As water runs downhill through burned areas, it can create erosion and undercut previously stable areas which causes large amounts of burned material (ash, sand, silt, rocks, trees) to become loose,” just like the river of black sludge they posted a video of. “As water and the material begin to move, the risk of damage to downhill areas increases.” (4)
According to the website, Pima County has been the eighth deadliest location for flood-related fatalities in the United States for the 20 previous years. The site encourages residents to create an emergency response plan and to buy flood insurance. (4)
The flash flood may not exactly be a river of black sludge, but it’s haunting nonetheless. And here’s to hoping we don’t fill in any more spaces on our 2020 hellscape bingo cards. (1)
