How "Offsite"

[radcontech]

I am planning on setting up an offsite NAS for backups. My question is how offsite is "offsite". For instance, I have a detached garage that I could put it in so if my house burnt down, water pipes burst, or thieves broke in and stole my stuff it would probably be fine. However, in the event of a local natural disaster I could loose everything. So how offsite do professional network people consider to be "offsite"? would my garage be ok or should I put it 100 miles away at one of my families houses?

Thanks!