Hi Caitlyn,

That would depend on how big the flare was. Normal flares might be lead to problems with radio communications and spacecraft, but they are not directly dangerous to people walking around on Earth's surface. Humans have been co-existing with the Sun and solar flares for a long time!

People have suggested that maybe a really big solar flare or other solar activity could have been a cause of one or more of the major extinction events that happened in the past (the best known one is the one that killed off the dinosaurs), but that is just speculation - I don't think there is any real evidence for it. It may be that the size of a solar flare is limited by the sizes of the sunspot regions on the Sun and they just don't get big enough.

Cheers,
Terry