This would not be without precedent: in 1859, the strongest recorded solar storm, known as the "Carrington Event", caused telegraph systems to fail or be shut down. But the world then did not have electronics, and water and power supplies did not depend on electrically-operated and computer-controlled machinery.
The facts of the sun's storm and ejection of vast quantities of charged particles appear to be corroborated by the amateur heliological website solarham.com:
Should we avoid going outside? Not clear: according to this Wiki article, ultraviolet light replenishes the ozone layer by splitting O2, so it is when the sun is "quiet" that the layer thins and more UV light penetrates to the Earth's surface. But there may be more UV health risk if you live in high northern latitudes, where the ozone layer is already thin or holed.
Indirectly, health and safety could be compromised by the failure of electrical systems that govern and provide for so much in our urban lives. Should we lay up extra water and cold food? It wouldn't hurt.
I like IPJ's idea of cowardy-custard politicians cowering in underground shelters; let's hope nobody superglues the locks.