Read in another thread (forget which) of a rumored fire at a bitcoin farm in Sichuan province at the time. There was no link to confirm and I could not find anything doing a search of English version of news from there.

EDIT: Mystery solved - https://bitcointalk.org/index.php?topic=855548.msg10958025#msg10958025

Spring Maintenance and Migration of miners to Bitmain Own facility from Umisoo.com facility

Only temporary!