These are the type and magnitude of impacts we would likely see during an ARkStorm-like event in California. It's possible such effects could be even more widespread, and affect more people, than this Southern Appalachian disaster, but the general point holds. [12/n]

Ultimately, there many folks in FL, GA, NC, & TN who are in need of urgent assistance--and that is/should be foremost priority. But to those insisting that "this is not the time!" to have those other conversations, I say: This is *exactly* when we need to be having them. [19/n]

But sometimes "worst case" scenarios really do come to pass, and I think we often lack the collective imagination to fully envision what that looks like. That's a problem, because being honest about risks that exist is first step toward mitigating them & preventing harm! [18/n]

As always, other factors are also at play: Expanding populations into known & extant floodplains as well as artificial modification of river channels; old and crumbling infrastructure built decades ago; differential societal exposure via economic inequity, and etc. [17/n]

The Sep 2024 event in Southern Appalachians has had "ARkStorm-level" impacts in eastern TN & western NC. Widespread, catastrophic flooding has resulted; many lives have been lost; transport, electric, telecomm infrastructure is devastated; some towns are completely isolated. [11/n]

Also, for my West Coast audience, I wanted to reflect on this event in the context of #ARkStorm#CAwater [10/n]

I'm writing this thread for a few reasons. First, I think it's important to recognize that this event is a disaster of national significance and will require large-scale response in both short and long term. "No news" is not good news in this case--quite the opposite. [9/n]

For a time yesterday, it appeared that multiple substantial and "high hazard" dams might fail entirely--sending large walls of water downstream and presenting an even greater disaster. Fortunately, it appears that catastrophe was narrowly averted--but only just. [7/n]

This was, by far, the most extreme rain event in observed record across much/most of the region, where reliable records date back over 100 yrs. Unsurprisingly, the flooding which resulted has also been widespread, historic, and generally catastrophic across a broad region. [3/n]

The images and stories just beginning to emerge from eastern TN and western NC in the aftermath of widespread catastrophic flooding wrought by #Helene#TNwx#NCwx [Thread: 1/n]