@Steve In Texas The Carrington event and huge magnetic storms in general are very low frequency and thus long wavelength in nature, they affect the power grid, which means your computers might temporarily go down though most data centers these days are ups and diesel or natural gas generator backed, communications relying on grid will go down, but these fields won't affect hard drives or small electronics consequently while your coin might not be accessible until power and communications are restored, it won't be lost. Modern grids are moving towards HVDC because it moves energy without the radiative loss and skin effect IR loss of AC power. These systems also are not impacted by geomagnetic storms.