Bloomberg, Sept. 12, 2014 (emphasis added): Solar Storms Sending Biggest Threats to Earth Today and Tomorrow — Airlines have rerouted some flights and global positioning system and radio transmissions may be degraded through tomorrow as two solar eruptions strike Earth and affect its magnetic field… When the ejections reach Earth, they will touch off geomagnetic storms that are forecast to last at least until tomorrow… Earth should be spared the most crippling impacts of these kinds of events, which can include disruptions to electric grids… what worries scientists [and] electric grid operators… is that they can get big and cause severe problems.
WFLA, Sept. 11, 2014: Two giant solar flares head to earth — Scientists warn two solar flares heading our way are some of the biggest seen in several years… A spokesman with Duke Energy [largest regulated US nuclear power company] tells us – “We are prepared to take action if needed, to protect our systems.”
Irish Examiner, Sept 11, 2014: A strong solar flare is blasting its way to Earth, but the worst of its power looks like it will barely skim above the planet and not cause many problems. It has been several years since Earth has had a solar storm of this size coming from sunspots smack in the middle of the sun, said Tom Berger, director of [NOAA’s] Space Weather Prediction Centre in Boulder, Colorado… the soonest it could arrive is late tonight UK time (early Friday in the US). But it could be later, Berger said… “There’s been a giant magnetic explosion on the sun,” Berger said. “Because it’s pointed right at us, we’ll at least catch some of the cloud” of highly energised and magnetised plasma that can disrupt Earth’s magnetic sphere, which sometimes leads to temporary power grid problems.
NOAA, Sept. 12, 2014: The second of the expected coronal mass ejections (CMEs) has arrived… storming is underway now and the forecast [is] for G3 (Strong) storming on the 13th.
NOAA Space Weather Scale for Geomagnetic Storms — Effect of G3 Storm on Power Systems: Duration of event will influence severity of effects… Voltage corrections may be required, false alarms triggered on some protection devices.
NBC News, Sept. 12, 2014: The sun shot out a double burst of electrically charged particles — known as coronal mass ejections, or CMEs — directly toward us… one accompanied a strong X1.6 flare on Wednesday… Berger said the storm could reach a strong G3 level by Saturday. That means grid operators might have to adjust the levels on their dials… It might also be harder to lock onto a GPS reading… Some planes that typically fly over Earth’s north polar region may be following different routes.
CBC, Sept. 10, 2014: The sun spot eruption caused a particularly strong solar flare… it registered as an X1, making it one of the biggest possible… CME can affect solar wind flow and “produce disturbances that strike the Earth with sometimes catastrophic results,” according to the [NASA] website.