Images taken by Efrain Morales Rivera (Puerto Rico) in the last few days (May 21-24) clearly show a changeable bright yellow streak of dust at the IAU western (following) edge of Eysium. The bright cloud was very conspicuous in red light and was not related to the usual orographic cloud activity over Elysium Mons.
Evidence for previous telescopic dust storms in this area exists, but such events are very uncommon for Elysium, and sometimes the area has simply been a secondary focus of activity for another dust storm developing elsewhere, such as at the start of the 2001 planet-encircling storm.
If you are able to do so, please monitor the area and send me your reports. Secondary activity could occur elsewhere at any time now, though an image by Clyde Foster centred at longitude 101 degrees on May 24 shows that hemisphere to be free of dust.
Best wishes, Richard McKim
The lower set of images provide evidence for strong South to North straight-line winds in the Hellas crater during April and early May 2016 or Ls 130 to Ls 150. Hellas is immense with the South to North diameter about 1,300 miles that is roughly the distance from the US-Canada border to the Pan-handle of Texas. So with that diameter, a significant temperature gradient is likely in the South to North direction that can produce strong winds. These detailed images by Clyde Foster and Efrain Riveras Morales show the results of these winds.