Last week, I did a quick graph of the number of tweets after the black rainstorm alerts. I repeated the procedure for the second black rainstorm alert in a week called by the Hong Kong Observatory. The tweets are grouped in intervals of five minutes and plotted over a course of four hours around when the alert is announced by HKO.
Nb of tweets found on searches for “black rainstorm” (vertical axis maximum is 30 tweets)
July 28nd black rainstorm alert (at 3:35PM)
July 22nd black rainstorm alert (at 5:30PM)
Of course, the graphs could mean a lot of things… One of my hypotheses (and perhaps most obvious answer) is that the first rainstorm of the season is always more captivating, tweet-worthy, than the second, let alone the third or fourth.
According to the HKO, a black rainstorm alert means: “Very heavy rain has fallen or is expected to fall generally over Hong Kong, exceeding 70 millimetres in an hour, and is likely to continue.”