If ammunition gets noticeably wet or is exposed to enough humidity that moisture enters the primer, then it can be deactivated. It takes a good amount of moisture and humidity to do so, and it usually happens in the case of repeat exposure — but it is certainly possible.
If this does happen, the primer will be deactivated as well as the propellant charge, which makes the ammunition completely useless. A tell-tale sign of any propellant charge or primer deactivation is to find rust or discoloration on the primer or the rim of the ammunition case. When you see discoloration or rust, you can be confident that the ammunition has lost its function and is unusable. That ammo in your photo is really corroded, most likely it's deactivated from water exposure, but to be on the safe side pick up a surplus metal ammo box, for storage when you transport.