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>Path: infoac!unido!fauern!ira.uka.de!sol.ctr.columbia.edu!emory!swrinde!ucsd!news-mail-gateway
>From: oler@HG.ULeth.CA (CARY OLER)
>Newsgroups: rec.radio.amateur.misc
>Subject: MAJOR SOLAR FLARE ALERT - 22 MARCH - STRANGE TYPE IV WITH 21 MARCH
>         EVENT
>Message-ID: <910322125723.224013dc@HG.ULeth.CA>
>Date: 22 Mar 91 19:57:23 GMT
>Sender: daemon@ucsd.Edu
>Organization: UCSD Usenet Gateway
>Lines: 66


                        --  MAJOR SOLAR FLARE ALERT  --

                                MARCH 22, 1991

                              Flare Event Summary
                          Potential Impact Assessment


                                    --------



MAJOR ENERGETIC EVENT SUMMARY

     Another major flare erupted from Region 6555 at a location of S25E35.
This event began at 08:33 UT, peaked at 08:40 UT and ended at 09:19 UT on
22 March.  There was a tenflare with this event, rated at 870 s.f.u..
Also, a 245 MHz burst was observed at an intensity of 12,000 s.f.u.  No
sweeps were observed.  The flare was fairly impulsive and had a low
integrated x-ray flux.  The event attained a class M6.3/1B rating.


POTENTIAL TERRESTRIAL IMPACT ASSESSMENT

     No terrestrial impacts are expected with this latest major flare.  It
had some moderately strong radio emissions but was not associated with any
sweeps and was an impulsive event.

     The most strange event which is really turning heads is the major
class 5.4/2B flare of 21 March (at 23:44 UT).  This event was not
particularly unusual as far as the flare itself goes, but the radio
emissions observed were very odd indeed.  The flare was associated with a
strong Type IV emission which drifted from low to high frequencies (it
should have been the other way around).  The emission increased in
intensity with time and reached very brilliant levels.  The event is STILL
IN PROGRESS at the time of this writing.  It has been categorized a
continuum Type IV emission.  It is perhaps one of the strangest emissions
observed in seven years.  Something is vigorously exciting the electrons
over that region, but no one knows what it might be.  The flare itself was
not extraordinary.  In fact, it was rather "average".

     There is a possibility that a Type II could have occurred with the
23:44 UT flare of 21 March.  There is uncertainty regarding this due to the
fact that the Type IV drifted from low to high frequencies and may have
"swallowed" the Type II emission.  So it is certainly possible that a Type
II could have occurred with this event (it would normally be observed with
a Type IV continuum emission as intense as this one has been).

     This event is very difficult to assess as far as potential terrestrial
impacts are concerned.  The flare itself was impulsive and of rather low
intensity.  But the wierd long duration Type IV continuum emission together
with the possible occurrence of a Type II is raising questions.  We
currently believe that a low to moderate risk exists for increased terrestrial
activity late on 23 March or on 24 March.  There is a slightly higher
probability that no terrestrial impacts will occur, but these predictions
are not associated with high confidence levels.  A Potential Geomagnetic
Storm Warning may be issued on 23 March just to cover the "bases."
Analysis of this odd event will continue.

     Major flaring is expected to continue from Region 6555.  Terrestrial
impacts from very energetic flaring could be high.  Watch for future alerts
and possible warnings.


**  End of Alert  **
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