re:
Recreating the array shouldn't lose your OS so it should just boot straight back up after it's finished building. It's all dependent on how you originally set up the array. I'd use an external dock and backup the important personal data off the drive prior to re-establishing the array, just in the off chance you do have to reinstall the OS.
Corruption of raid array's could be caused by the following:
1. A physical fault with the drive, I.E... Bad Sectors
2. Could be caused by logical I/O errors when writing data to the disk.
3. Power surge
4. Raid parity can become corrupt due to System Crashes, or hard resets (without using the OS shutdown function).
5. Uncorrectable bit errors which cause bunches in the magnetism of the disk, which in turn prevents data from being stored within that portion of the disk.
I'd recommend if you haven't already, use a surge protector on your power supply and also follow good practice and never hard power off your PC (That's if you do it). I'd recommend once you rebuild the array, run a program like HDD Regenerator v1.51 and do a thorough scan of your disk for bad sectors (caused by physical damage). If none appear using this program, then it's safe to say that it isn't #1 above but potentially a bad write or system crash that caused the raid array to become corrupt.
Hope that helps. There's a lot of other reasons why it would corrupt but these are the most common reasons.