A partial halo Coronal Mass Ejection (CME) was observed early on 15 March 2015 from active region 2297 near the centre of the solar disk. Traveling towards Earth at an estimated speed of ~800 km/s the CME impacted the Earth's magnetic field and caused a strong geomagnetic storm with a maximum Kp value of 8 observed. The local K-index of Hermanus reached 7 and the Dst index was -228 nT which indicates a strong geomagnetic storm.
This is the strongest geomagnetic storm during the current solar cycle 24 and the largest observed storm since late 2005. SANSA Space Weather Scientist,Teboho Nxele said "this is the longest and most disturbed magnetic period I have observed since 2011."
SANSA Space Weather Centre issued warnings of possible HF communication blackouts and possible disturbances to navigation systems. SANSA Space Weather Practitioner, Mpho Tshisaphungo siad "HF propagation frequencies are way below expected values due to such a strong geomagnetic storm."