All modern telecommunications are over fibre or radio links.
Power lines might be the most vulnerable part, actually. The geomagnetic field can induce current that will bias the core of transformers, causing them to overheat. This can lead to blackouts if the networks are close to capacity, and it's suspected that the 2003 North East Blackout was at least partially caused by them.
Essentially, components that kick in when a voltage exceeds a certain limit to allow that excess voltage to shunt to ground instead of continue to build up in the circuit.
Similar devices in pneumatics or hydraulics are pressure relief valves [https://en.m.wikipedia.org/wiki/Relief_valve], and they provide similar functionality - giving a easier/lower resistance path for the high voltage/pressure, so delicate things downstream don’t fail.
I have no idea what the correlation is between particle flux (the metric reported here) and actual geomagnetic variation which induces the current (varying magnetic field causes voltage). Basically the charged particles zoom past earth, then loop back from the magnetotail towards the poles. The magnetohydrodynamics cause effects large enough to modulate the magnetic field on earths surface.
”We have this long conducting loop” is the issue. The Earth is one component of the loop.