Mars' dark streaks are probably caused by dry landslides
"The evidence continues to mount.
These characteristics led scientists to speculate that the dark marks could be caused by salty liquid water flowing or seeping through the red dirt, in spots that get warm enough for some of Mars' plentiful subsurface ice to melt. That exciting hypothesis got a boost in 2015, when data gathered by MRO's Compact Reconnaissance Imaging Spectrometer instrument, or CRISM, revealed the apparent signature of hydrated salts at some RSL locales. That's just what you'd expect to see after briny liquid had evaporated away.
But the liquid-water explanation has been losing favor over the last few years. "
Still think the Cornice Avalanches on Mars hypothesis is the best. :-)
Helicopter on Mars could investigate RSLs.
"4Recurring Slope Lineae:RSL are special regions that are difficult to explore without danger of contamination. However, a helicopter could fly or hover over RSL without touching them. Spectral properties, daily changes and the timing of appearance and fading behaviors, and nearby moisture and wind content could all reveal the true nature of these enigmatic features."
Exploring RSLs a High Priority
"•Mars 2020 can acquire valuable new knowledge about RSL–Can image through all times of day, so wetting and drying soil should be obvious. MRO can only observe near 3 PM, the driest time of day.–If rover can get close enough for SuperCamto acquire compositional data, that would be extremely valuable–MEDA data near RSL site would be very valuable to understand origin of water
•Understanding RSL may be key to future human exploration–They need water to survive, and equatorial landing sites are best for thermal management•No known shallow ice in equatorial regions, so RSL are best candidate indicators of water•If origin of RSL water is atmospheric, do these sites show where it is easiest to extract water from the atmosphere?•If RSL water is from the subsurface, then habitability is more favorable
•In conclusion, Mars 2020 landing near an RSL site would be most excellent for Mars science and future exploration"
Video showing dust and ice avalanche on Mars.
Getting closer and closer. Looks a lot like RSLs in capture from above video. Click to expand.
