Arizona Wildfires

  • Arizona megafire burning out of control, thousands evacuated

    Arizona emergency crews are working to put out a massive wildfire.

    The blaze, dubbed the Bush Fire, ignited last Saturday and has more than doubled in size since Wednesday morning. It has burned more than 150,000 acres, so far.

    Now defined as a megafire – because it has already burned more than 40,500 hectares (100,000 acres) of land – the seventh largest fire in state history burns out-of-control and is only seven percent contained, ravaging parts of the Tonto National Forrest, just northeast of Phoenix.

    The ‘Bush Fire’ has grown dramatically in size from 59 square miles to 101 square miles as of Tuesday morning officials said.

    The good news is no homes nor businesses have been destroyed, but some worry it is just a matter of time, as evacuations have been implemented in multiple towns and officials are urging residents to evacuate to nearby shelters.

    The wildfire has forced evacuation of thousands of people in several rural communities in Maricopa and Gila counties and closed parts of numbers of roads, among others State Route 87, or the Beeline Highway, from Payson to Bush Highway and State Route 188 from the 87 junctions to Roosevelt.

    While residents are evacuating their homes, the Red Cross has been setting up shelters. Moreover, many Arizonans from Punkin Center, Sunflower, and Apache Lake are now sleeping in motels.

    As 440 firefighters desperately try to squelch the inferno, hundreds more are praying for them. “I think everybody is just terrified and hoping they will get it out in time before the residences are lost,” said Hill. “Let’s stop it on the highway, please. And before the homes.

    Fire officials say the fire started due to a car issue on the side of the highway.

    Other fires burning in Arizona and California

    Meanwhile, other major fires also are burning across the state amid hot, windy and dry conditions, including two that also have prompted evacuations of threatened rural communities in several other parts of both Arizona and California.

    The two other major fires in Arizona spread in the Santa Catalina Mountains overlooking Tucson in southern Arizona (BigHorn Fire) and in the Kaibab National Forest north of the Grand Canyon in northern Arizona (Mangum Fire):

    • Near Tucson, hotshot crews were able to gain 30% containment of the 14,686-acre Bighorn Fire in the Santa Catalina Mountains as of Monday night. 
    • The Mangum Fire has burned for over a week near the Grand Canyon’s North Rim, overtaking more than 29,000 acres in the Kaibab National Forest with 3% containment as of Monday.

  • River of Black Sludge in Arizona

    On 15 July 2020, what looked like your typical dry waterway was engulfed by a sickening dust puffing black sludge, reminiscent of the villainous cartoon toxin, Hexxus from FernGully: The Last Rainforest.

    The Cañada del Oro Wash in Arizona became choked with this monstrosity – known as a sediment slug – after what officials said was a minor storm, while the Bighorn Fire raged nearby.

    Debris flows like this one from the Bighorn Fire in Arizona can be deadly.

    The debris fuelling the Bighorn Fire was thought to have been ignited by lightning; the fire has engulfed over 48,377 hectares (119,541 acres) of national park since June 5 in a region that covers diverse ecosystems from saguaro cactus stands to pine and fir forests. While it’s been brought under control, the fire is still burning the foothills of the Catalina mountains.

    As if wildlife doesn’t have enough to contend with after fires scorch their landscape, fires make future rains dangerous, too.

    “Wildfires like the Bighorn Fire leave the ground charred, barren, and unable to absorb water,” Pima County officials wrote on Twitter. “Even a light rain can produce devastating flash floods and mudflows, often with little warning.”

    Fire changes the structure of the soil by mineralising organic matter and releasing nutrients, metals, and toxins that usually aren’t free to be swept away by water. The new soil structure then repels water. 

    “It takes much less rainfall to trigger debris flows from burned basins than from unburned areas,” USGS’s California Water Science Center explains. “In Southern California, as little as 7 millimetres (0.3 inches) of rainfall in 30 minutes has triggered debris flows.” 

    With the loss of vegetation holding the soil in place, the ash and loose earth end up smothering waterways. This reduces dissolved oxygen levels, while increased nutrients allow cyanobacteria to grow and algae to bloom, which take up even more of the oxygen.

    The eventual lack of oxygen suffocates fish, crabs and other waterway wildlife, leading to mass deaths like those seen after Australia’s unprecedented 2019-2020 summer of bushfires.

    If the fish and other wildlife somehow survive all that, they may then starve to death, unable to see their food as the clouded water reduces visibility, and starves aquatic plants and algae of the light they need to photosynthesise.

    Sediment slugs can also ooze their way into dams and threaten our drinking water, making mud too thick for filtration systems to cope with.

    When large solid debris also joins the fast-moving sludge, it contributes to the erosion of anything in the way of the flow, including destabilising roads and paths, and posing risk to water treatment infrastructure.

    “Fast-moving, highly destructive debris flows triggered by intense rainfall are one of the most dangerous post-fire hazards. Such debris flows are particularly dangerous because they tend to occur with little warning,” explained a USGS in a report.

    “Debris flows can strip vegetation, block drainages, damage structures, and endanger human life.” 

    Ecologist Paul McInerney from CSIRO and colleagues explained in an article on The Conversation that using sediment barriers and other erosion control measures may be able to limit the size of these sediment slugs.  Ensuring waterways are re-vegetated can also help in the long term.

    But these events can lead to decades of impact. In some cases fish populations never recover, ecologist Lee Baumgartner told The Guardian, pointing to 1939 bushfires that destroyed fish populations in Australia’s Lachlan River.

    Of course, limiting wildfire-fuelling climate change would be the ultimate way of reducing the occurrence of such slimy sediment slugs. But perhaps, like Hexxus, we’re just too in love with our toxic sludge.

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