Powder and Humidity

[Species]

I recently returned from a vacation in California.  The humidity was extremely high due to rain the days we were there.  I live in Utah which is one of the driest climates around in terms of humidity.  Anyway, as a special treat to the kids we bought a Costco sized box of Oreos for the vacation.  It was amazing how fast the Oreos went "soggy" when we left an unopened sleeve on the table.  In Utah I can leave Oreos in an open sleeve for days and they don't taste "stale" or "soggy".  Leave them open for a couple hours in high humidity and they are soggy and the kids wouldn't touch them......

So, that leads me to my question:  how does powder hold up in high humidity climates?  I think I could store powder and primers in my closet with no special precautions almost indefinitely, but I can't help but wonder what humidity does to components over the long run.  Anyone have any issues with components and living in humid regions?  Just curious 

[The_Shadow]

Modern smokeless powders & primers are not very hydroscopic (meaning they don't tend to absorb moisture).  They have stored smokeless powders in water for years and dried it out to function without any loss of potency.  Primers are formulated as a wetted mix and dried out at low temp and humidity till they reach they desired sensitivity.

I keep my primers in plastic ziploc bags down here in Louisiana, even though they are stored in an AC/heat controlled climate inside.  I have shot some of my ammo that was over 20 years old, coming in at the same velocity as newly loaded stuff.
My B-I-L who loaded his 9mm ammo on my press, had 500+ 9mm rounds get swamped by the floodwaters of Hurricane Katrina, stayed under water of weeks, then dried off and cleaned, were fired as target ammo with only one round going dead.  Power was fine the primer died, change the primer and it was go to go as tested.