Sorry, Rob, I *can* be a bit gruff at times.

I still think this paper requires cautious assessment. My concern is that they have chosen very lightweight materials (but of course, the dusts of Mars could be equally light), and that they are working at a very small scale. These factors tend to encourage atmospheric entrainment and fluidisation.

Essentially, they're making mini-avalanches in the lab, and showing (as I've argued for years) that the morphology matches many aspects expected from liquid flows.

It's a great paper in that it shows real gully-like structures, which is ammunition against the people who oppose gas-fluidised models almost on principle.

I still think you need a better and more active involvement of volatiles to generate a larger scale flow on Mars (100 m to 1 km long).