Here is some info...
SOLAR TSUNAMI: When sunspot 930 exploded on Dec. 6th, producing an X6-
category flare, it also created a tsunami-like shock wave that rolled across the face of
the sun, wiping out filaments and other structures in its path. An H-alpha telescope in
New Mexico operated by the National Solar Observatory (NSO) recorded the action:
and an animation of the wave
regards,CS sunny days
Rob
PS: I guess this is why we're not seeing too many surface filaments
at present.