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You're asking the wrong question. Flares themselves are mostly energy, and when they're called 'flares', they tend to be optical wavelengths or lower (EUV, x-ray, etc.), and it's moving at the speed of light, so there's really nothing you can do to protect yourself against them as we don't have any sort of warning. They *can* damage satellites, particularly those that are directly solar observing (a couple of years ago, one of the GOES SXI telescopes was in the middle of commissioning, taking a 25 min exposure during a flare)
The question you should be asking is about solar activity in general, as flares are often the precursor of other types of activity. Radio Bursts are similar to flares, but in lower frequencies; the main issue with them is that they're effectively noise, so if they're at the GPS frequencies, or something else that uses a rather weak signal, you can't hear it. So a few years back (2006? 2007?), there was a day when GPS was effectively useless.
You also have Solar Energetic Particle (SEP) events, where you have highly energetic particles which can do nasty things to electronics and people in space. Our atmosphere and magetic field shields us from most of it, but the way the magnetic field shields us, it actually concentrates things at the poles, which is why some airlines won't fly the trans-polar flights during periods of high solar activity. For humans in space without the atmosphere, strong enough storms could kill them from radiation. For satellites, it can cause damage to solar panels or electronics or more subtle things like flipping bits in memory.
You also have Coronal Mass Ejections (CME), which are larger clouds of material ... they're slowing moving, so we might have time to do something to protect against them, but the big problems is that they often have a magnetic charge, and depending on the direction of if, it can partially cancel out the earth's magnetic field. It can also induce current in long wires, which if strong enough can cause damage to the power grid, particularly at high latitudes.
You can get more information on frequency of these events from NOAA's Space Weather Prediction Center: http://www.swpc.noaa.gov/NOAAscales/ ; note that a 'cycle' in this context is about 11 years.
Disclaimer : I'm not a solar physicist, but I do IT support for them. If you want an authoritiative answer, ask Alex Young : http://www.thesuntoday.org/