This is what Spaceweather.com said about the event.
IMPULSIVE SOLAR FLARE SCRAMBLES RADIO SIGNALS: 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:
CHANCE OF STORMS: The first of three or more CMEs en route to Earth are expected to arrive late in the day on April 1st. None of the incoming clouds is squarely Earth-directed. The series of glanciing blows, however, will rattle Earth's magnetic field and possibly spark auroras. NOAA forecasters estimate a 60% chance of polar geomagnetic storms on April 2nd.. Aurora alerts: text, voice
The first paragraph covers the actual flare itself which was a powerful 'X Flare'. The effect of this was immediate, or 8 minutes later, with some short wave radio signals being affected.
Presumably this flare and others at around the same time, ejected 'CMEs', Coronal Mass Ejections, or massive clumps of Solar material which, when making contact with the Earth's magnetic field, will form the Northern Lights. From what I can see, they are not expecting a massive display, but I was wrong once before, I think!
