Helpful+&+Interesting+Reading

A) Particle/turbulence interactiontoc
The following paper on saltation of sand grains in a wind tunnel just appeared in EPJ E. I have not read it, though, and the abstract indicates that it mostly confirms earlier results by other authors. (Dieter, 2013-11-19)

At the recent Intl. Snow Science Workshop 2013 in Grenoble, Bartelt et al. presented photogrammetrical measurements of the wakes produced in powder-snow avalanches at the Vallée de la Sionne test site in Switzerland. I have some doubts concerning certain interpretations offered in the paper, but the experimental data may be interesting for comparison with measurements on turbidity currents in estuaries (see Ray Kostaschuk's talk) and in water tanks (cf. Joris Eggenhuisen's work). (Dieter, 2013-11-19)

B.I)
1. Transfer of energy or not between colliding grains of natural shape

C) Morphodynamics
Bed forms on Mars: http://www.nasa.gov/content/two-generations-of-windblown-sediments-on-mars/#.UkmenpU2-lI

A field study of aeolean sand ripples from 1964 by Sharp: A Master's Thesis on sand ripples by Walker from 1981 with extensive wind tunnel data:

D) Aeolian transport of snow
An old bibliography (in BibTeX format) on snowdrift, collected by Jim McElwaine and slightly enlarged by Dieter Issler: These files translate the journal codes to the full and abbreviated names of the journals:

Here are some [|snow barchans] A [|snow barchan] in Antarctica. There may be some resemblance to sand dunes also for other [|Antarctica dunes] Some relevant papers may be found [|here]

There was quite some discussion about the saturation length. The following 1980 paper by M. Takeuchi contains measurements on the evolution of snow mass flux towards saturation:

Incidentally, today (2013-11-21) a paper alluded to by Hans Herrmann in hs talk appeared in PRL: http://prl.aps.org/abstract/PRL/v111/i21/e218002 Here is the abstract: "Sediment transport along the surface drives geophysical phenomena as diverse as wind erosion and dune formation. The main length scale controlling the dynamics of sediment erosion and deposition is the saturation length //L////s//, which characterizes the flux response to a change in transport conditions. Here we derive, for the first time, an expression predicting //L////s// as a function of the average sediment velocity under different physical environments. Our expression accounts for both the characteristics of sediment entrainment and the saturation of particle and fluid velocities, and has only two physical parameters which can be estimated directly from independent experiments. We show that our expression is consistent with measurements of //L////s// in both aeolian and subaqueous transport regimes over at least 5 orders of magnitude in the ratio of fluid and particle density, including on Mars." (Dieter, 2013-11-21)

Some of the first slides in a pictures-only presentation by R. Lambert at the Intl. Snow Science Workshop earlier this month in Grenoble shows the role played by suspension on the one side and cohesion on the other in aeolian transport of snow in the mountains:



E) The problem of transforming slide material
A 20 minutes video with good commentary on the 1978 quick-clay slide at Rissa, Norway: http://www.ngi.no/en/Areas-of-research-and-development/Soil-and-rock-slides/The-Quick-Clay-Landslide-at-Rissa---1978/

F) Levee formation
Similar levee formation as shown for debris flows by Chris Johnson in his presentation can also be observed in granular wet-snow avalanches. Here is an instructive video from near Innsbruck, Tyrol, Austria. I downloaded it from http://video.news.com.au/v/116770/Amazing-avalanche-in-Austria, but do not know who took it and where exactly it happened.

media type="file" key="Nassschneelawine_Innsbruck.mp4" width="300" height="300"

The following video shows tendency for levee formation in the later phases of the flow. Presumably the avalanche, whcih started out as a dry-snow avalanche, picked up more humid snow further down. In addition, one can observe several phenomena that are important in connection with snow avalanches:
 * The speed of fracture propagation (both primary and secondary fractures),
 * The initial break-up of the slab,
 * The fluidization of the head
 * Jets shooting out at the front (presumably some instability right behind the front),
 * The formation of the powder-snow cloud, particularly during the fall over a cliff

I lack precise information about the date and location of the event. The avalanche is released artificially by explosive deployed from helicopter, which narrows the choice to only a few countries. (Oops -- the file is too big to upload! If you are interested, I can show it to you on my laptop. Dieter)

Just got a presentation from the Intl. Snow Science Workshop 2013, held a couple of weeks ago in Grenoble, which consists essentially of pictures of snow and avalanches only. One can see the following things, among others: The presentation is by Richard Lambert.
 * Levee formation in wet-snow avalanches
 * Fingering in wet-snow avalanches



G) Debris flow / levee formation videos
The [|1984 USGS video report on Debris-Flow Dynamics] by Costa & Williams is available on YouTube, at [] (part 1) [] (part 2) [] (part 3) Albeit at fairly low picture quality, theres an enormous range of flow behaviour captured in this film. The section illustrating the 'tank-treading'/over-running and lateral divergence near the flow front used in my (Chris Johnson's) talk is at 4:15 in part 1. Some interesting sediment remobilisation/deposition solitons are shown from 2:05 in part 3