> Marine Traffic Control said the backlog is primarily due to weather conditions, including several days of fog at the canal. But we spoke with a canal insider, who said that in his decades of experience he has only seen it like this when there is some other issue going on – not one that’s weather related.
Thus, something is happening behind the scenes that they don't want to talk about.
Maybe there is political pressure from Nicaragua/Hong Kong proponents of the Nicaraguan canal. The biggest reason cited by the WSJ not to build the canal is lack of demand:
http://www.wsj.com/articles/china-wants-to-dig-the-nicaragua...
It's quite possible that Nicaragua/Hong Kong are putting pressure on Panama to increase the wait times. Perhaps they scheduled the "Dry chamber maintenance" during a high-shipping seasons on purpose:
> A statement provided to us Friday from the Panama Canal Authority said that a high level of arrivals during the last in September coincided with schedule dry-chamber maintenance.