"These large scale 'blast' waves occur infrequently, however, are very powerful. They quickly propagate in a matter of minutes covering the whole Sun, sweeping away filamentary material," said Dr. K. S. Balasubramaniam. "It is unusual to see such powerful waves encompassing the whole sun from ground based observatories. Its significance comes from the fact that these waves are occurring near solar minimum, when intense activity is yet to pick up."
SpaceWeather.com has a nice 480x360 GIF animation showing the wave spreading across the surface of the sun."