[shagie]

Not powered, but the next room over is acceptable for a solar flare.

The issue would be that wires start getting induced current in them ( https://en.wikipedia.org/wiki/Geomagnetically_induced_curren... ) that arcs and shorts out the device.

However, if you've got a backup tape there's nothing from the current that will flip the bits on the tape itself.

There are good reasons to have the backup be off site (other physical calamities) - but the aurora isn't going to flip any bits on a backup. At worst, it will destroy the machinery from a surge from the grid and an extremely powerful one may destroy the machinery from arcing in the device itself (this would be extremely powerful)... but the media itself is fine.