On Saturday, March 29th, the magnetic canopy of sunspot AR2017 erupted, producing a brief but intense X1-class solar flare. A flash of extreme UV radiation sent waves of ionization rippling through Earth's upper atmosphere and disturbed the normal propagation of terrestrial radio transmissions. Radio engineer Stan Nelson of Roswell, NM, was monitoring WWV at 20 MHz when the signal wobbled then disappeared entirely for several minutes: