[gleeaikin]

I forgot to include this article also on the mars story.

http://www.aol.com/article/2015/02/17/scientists-baffled-by-mysterious-haze-on-mars/21143468/?ncid=webmail11

[SunkenCiv]

Thanks g. None of the sources I've been able to read (the Nature source might be nice, but it requires authorization) say that there have been multiple events in the same spot -- merely that two amateurs saw a similar phenomenon twice (well, three times) in 2012. Here's the snip from the BBC piece linked out of that AOL piece.

The vast plume was initially spotted by amateur astronomers in 2012, and appeared twice before vanishing. Scientists have now analysed the images and say that the formation, stretching for more than 1,000km, is larger than any seen before. The vast, bright haze lasted for about 10 days. A month later, it reappeared for the same length of time. But it has not been seen since.