I had previously made this thread: http://www.gamesas.com/topic/1593838-crashing-when-it-rains/to document this problem.

I'm happy to report this problem is gone now with the Crimson 16.3.1 driver update. I have ran around for 30 minutes across multiple areas all when it starts raining without a single crash... usually I wouldn't last more than a couple of minutes, most of the time no more than 30 seconds.

Although the driver doesn't say anything about fixing this in the driver notes, someone from AMD on their support forums hinted that people having this similar problem in Far Cry Primal should try the driver and a lot of reports came back saying it had fixed the FC:Primal issue so I tested it in Fallout 4 and it seems to hold there as well.

So anyone who had this issue I fully recommend you go and update your drivers to the 16.3.1! remember to use Display Driver Uninstaller first just to be sure! Also remember to turn off the Power Efficiency setting in the drivers again when you're done.

Thanks.

Good to know

Glad you fixed your problem!

I guess it's time for AMD to wake up (Hello, anybody home?), and fix their damn drivers once and for all...

Well said. I could go on ........................ but I'll spare you

After reading this i popped my R9 380 back into the pc and tested it.

I went to Sommerville Place and ran around in the rain.

Yay, no crashes experienced in the rain.

Sadly still seeing the rainbow textures problem after a while, though.

One problem at a time I guess

Yeah. Vulkan is installed.That is your new API.

It was nothing to do with Vulkan. First of all, merely having Vulkan won't make Fallout 4 use the API, so it can't have fixed it for that reason. But even then, Vulkan first came in the 16.3 drivers and they didn't fix the issue, it wasn't until the 16.3.1 driver which someone from AMD hinted contained the undocumented fix that the problem was resolved.