[ellisd]

The last emergency AM broadcast I recall being relevant to my life in the United States was the 1994 Northridge Earthquake, pre-SMS. All the copper phone lines were overloaded from calls and this was the only medium to receive information.

Our family sat in the minivan in the driveway and tuned to KFWB News 980 AM right as their station returned to air on backup generators.

https://en.wikipedia.org/wiki/KFWB

It no longer broadcasts news, but AM station KNX could/would effectively do the same.