From n3kl.org
GEOPHYSICAL EVENTS. Flares (Importance two or larger) with Centimetric
Outbursts (maximum of the flux higher than the Quiet Sun flux,
duration longer 10 minutes) and/or strong SID. Sometimes these
flares are followed by Geomagnetic Storms or small PCA. (Class M
Flares)
Normal: Solar X-ray flux is quiet - No problem/
Active: Solar X-ray flux is active - Wear sun protectant and sun glasses/
M Class Flare: An M Class flare has occurred - Stay out of the sun-skin cancer potential/
X Class Flare: An X Class flare has occurred - Cell phones and TV's may go in and out/
Mega Flare: An unprecedented X-ray event has occurred - Stay inside/
Quiet: the Geomagnetic Field is quiet/
Active: the Geomagnetic Field has been unsettled/
Storm: A Geomagnetic Storm has occurred/
GEOMAGNETIC STORM. A worldwide disturbance of the earth's magnetic field,
distinct from regular diurnal variations.
