[observationist]

https://downdetector.com/

If you take a look, you can see comparable bumps during events like these across a wide array of sites and services, indicating a shared point of failure. Given the extreme weather, it's a tossup as to whether this was a fiber cut or a config screwup - could be bad BGP or routing, or possibly even an intentional cutover in preparation for possible outages, swapping primary and backup.

Lots of possible root causes, and it's at a level that consumers probably won't get a clear answer right away.