Turn signal bulb "explodes".

[Hankster]

Explodes might be a bit of an exaggeration, but twice on a recent trip in our 25ft. 97 Safari the right signal stopped working. Took off the cover and the bulb had a popped with a 1/2 inch hole at the top of the bulb. Put the cover on tight, but could water leak from rain cause this ? We did encounter some rain. Bad gasket? Thanks.

[Rich W]

You've diagnosed your own problem
Water is getting on the bulb when it's hot and it pops. Now you have to figure out where the water is coming from. The gasket is the most likely culprit, either worn or installed improperly. It's also possible that there is a crack in the lens.

If it was mine I'd clean up the lens and replace the gasket. If the gasket is new then I'd use some Oatey plumber's silicone on it (Lowes, HD). Make sure it's lined up properly before tightening the lens.