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In the extended model the flowing avalanche core ($\Phi$) consists of clumps and clods of snow (granules); the cloud consists of mixture of air and ice-dust ($\Pi$), see Fig. 1. The core is physically treated as a gravitationally driven, granular shear flow; the cloud is modelled as an inertial, turbulent suspension. Because the snow material in the core is non-suspendable and the ice-dust in the cloud is suspendable, two flow layers exist simultaneously, but with different flow densities ($\rho_{\Phi}$, $\rho_{\Pi}$) and speeds ($\textbf{u}_{\Phi}$, $\textbf{u}_{\Pi}$). The layers are formed by natural segregation because of the large difference in particle sizes – dust (< 1mm) and granules (>1cm) – and therefore settlement speeds. 


Random Kinetic Energy

The Random Kinetic Energy (RKE) approach splits the shear work rate into the production of thermal and granular temperatures.


Avalanche interaction with the snowcover is physically treated as an elastic-plastic collision in which snow can be entrained (plastic collision).


It has long been recognized that warm, moist snow behaves differently than cold, dry snow.

The Formation of the Powder Cloud

The avalanche cloud is mathematically treated as an inertial, turbulent suspension.


The forest module applies the detrainment method developed by Feistl et al. 20??.

Pressure Modules

The RAMMS::Extended model contains two pressure modules.