What happens if a solar flare hits Earth? When solar flares do hit Earth, they can wreak havoc to electronics and communication systems. NOAA warns that GPS systems and radio signals can be disturbed by a solar storm.

Very high-energy particles, such as those carried by CMEs, can cause radiation poisoning to humans and other mammals. They would be dangerous to unshielded astronauts, say, astronauts traveling to the moon. Large doses could be fatal. Still, solar storms  and their effects  are no problem for us on Earth's surface.