I think some of these traditions also persist in Pennsylvania. The Pennsylvania Dutch serve a doughnut called a fastnacht on Shrove Tuesday/Mardi Gras/the day before Ash Wednesday, and Basel's Fasnacht and the Philadelphia mummers parade almost certainly share some cultural DNA.
To add to the melancholy: Fasnacht in Basel was cancelled twice during covid. That hit many people very hard. A small group played two well known tunes (one in a minor key instead of the usual major) up one of the towers of the minster to symbolically carry Basler Fasnacht to its grave (downstairs the police was trying to get the door open because they did not know about it). The performance is haunting and is of course on youtube: https://www.youtube.com/watch?v=ge7LRIPKREA
I highly recommend the Morgenstreich. It's really an amazing experience and it's awesome to think you are sharing the same experience as people continued to do for hundreds of years.
It's fascinating to see how deeply embedded Fasnacht is in the local culture, especially when you live in the heart of it. My kids are always talking about it all year round, eager to play the drum themselves. You can hear the music of drums and pipes weekly in the evening as people practice, preparing for those three days. It’s truly a life-long commitment for many and absolutely beautiful when it starts out of nothing at 4‘o clock in the night and vanishes as fast three days later.
I lived in Switzerland for a few years as a kid and used to love Schaffhausen's Fasnacht. I'd actually totally forgotten about it until seeing this post!