Look at Waze to see what's actually happening, like I always do.
And frankly, even if you did have a signal, it's not likely Waze will be of much help. There are often few travelers on that road, and chances are none of them is using Waze.
US2 over Stevens Pass near me has a similar useless warning that some miniscule percent of drivers ever tune in to. The AM radio broadcast us just going to say to use caution because rocks may appear on the roadway unexpectedly. A normal person is able to infer that caution is needed based on the terrain and the “rock slide information broadcast” sign.
It's not a Tesla thing, really, it's an EV thing. You'll have to stick with ICEV for the foreseeable future if you need access to AM. The electric motors cause a lot of interference.
[0] https://www.thedrive.com/news/heres-why-some-automakers-tune...
Reason #27 for not buying a Tesla. When you're on the highway and see the flashing lights saying "Tune to 520 AM for adverse road conditions" what are you going to do?