You might consider a marine-band VHF. Â There are 4 weather bands, one or two of which are usually useable in a particular area. Â I use them for updated weather info, especially while in a boat, but it’s handy for hiking, too. Â I don’t know if tsunami warnings are conveyed through them or not, but I’m sure radio traffic would be abuzz about it if one was issued. Â 4 minutes after that 7.8 earthquake we had two weeks ago, we all got tsunami alerts through our cell phones.
And if you want a boat to rescue you off of a beach, it’s the best thing to have. Â You can ping most any boat you can see and some just over the horizon and in more populated areas, a distress signal can be passed on by Coast Guard radio repeaters. Â And it’s two-way, so you can communicate what your problem is, instead of hitting a panic button without additional information.
You’re not supposed to use them on/from land, but in an emergency, I doubt anyone would object.
When I’m in a small craft, I ALWAYS have a life jacket on. Â And my life jacket ALWAYS has my compact VHF radio secured to it (and some other goodies).