This study analyzed quantitative big data from web news on the West Japan Heavy Rain disaster for a two-month period. The retrieved information was compared with previous natural disaster coverage. The results indicated the following. 1) For natural disasters that had occurred over the past 15 years, the “half-life period for media exposure” (i.e., the period in which the amount of news reporting halves) was approximately one week, while the half-life period of web media exposure on the West Japan Heavy Rain disaster was 24 days. Thus, the West Japan Heavy Rain disaster appeared to be the most significant social concern since the Great East Japan Earthquake. 2) The West Japan Heavy Rain disaster was large enough to affect both the Chugoku and Shikoku Districts, but the available human support was comparable to the extent of the human and material damages as well as the related amount of media coverage. No significant regional differences in the amount of media coverage or support were found.

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