This is a copy of NOAA's "event listing" information for this flare. From this
one discerns that it happened in NOAA active region number 9393; it had a
huge microwave flux (14,000 solar flux units, or 1.4 x 10^(-18) W/m^2.Hz,
at 15,400 MHz), an X20 X-ray classification (2 erg/cm^2.sec), etc. - no
mention of the traditional H-alpha classification, probably because it
has not been officially generated at the time of writing here, April 5.

#
#Event    Begin    Max       End  Obs  Q  Type  Loc/Frq   Particulars       Reg#
#-------------------------------------------------------------------------------

7810 +     2132   2149      2316  PAL  G   RBR  15400     14000             9393
7810 +     2132   2151      2203  GO8  5   XRA  1-8A      X20     1.5E00    9393
7810 +     2135   2147      2327  PAL  G   RBR  4995      5500              9393
7810 +     2135   2147      2321  PAL  G   RBR  8800      7600              9393
7810 +     2144   2148      2323  PAL  G   RBR  1415      4400              9393
7810 +     2144   2253      2321  PAL  G   RBR  2695      10000             9393
7810 +     2146   2152      2214  SAG  G   RBR  245       45000             9393
7810 +     2146   2150      2205  PAL  G   RBR  606       940               9393
7810 +     2148   2149      2201  PAL  G   RBR  410       710               9393
7810 +     2152   ////      2157  CUL  C   RSP  28-280    II/3              9393
7810       2152   ////      2153  CUL  C   RSP  30-280    III/1             9393