"No activity detected" ? Why did they issue the alert ?

Peace +

"Mike Terry" wrote in message ...
Sent: Friday, January 07, 2005 11:01 PM
Subject: [AuroraWatch] Red alert issued 23:01 UT 07 Jan 2005


AuroraWatch Alert, 23:01 UT 07 Jan 2005:
VERY LARGE increase in local activity, possible SSC.
http://www.dcs.lancs.ac.uk/iono/aurorawatch/

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[re earlier posting - chances of hearing Scandinavian Weekend Radio
diminished by auroral activity]

(BDXC)