Azure is the #2 cloud platform on Earth, so your last statement is bunk. The outage is very localized, none of my instances in South Central were ever "down," there was a brief 5-10 time frame when I noticed CPU spikes, I assume from a rebooting process from mitigation...which effected some availability but it was never truly down.
The problem was caused by a power surge to their cooling system, which eventually led to systems shutting down to prevent overheating.
The main thing is the spill over from authentication, which is effecting other regions. This isn't an AWS/GCS type even where every service suddenly cascaded. My portal is still not 100% functioning, but all of my services are operating normally and are up. So it's probably at this point only effecting AD and provisioning rather than service SLA.