Snow & Ice formula solvers
Compactive Viscosity of Snow (Kojima)
Snow & IceSoil MechanicsStrength of MaterialsThe compactive viscosity of snow, rising exponentially with its own density — Kojima's 1967 relation, in the form Anderson's SNTHERM and most land-surface schemes have used since. It is why snow settles fast on the first night and then almost stops: the act of compacting is what makes it resist compacting.
Compressive Strength of Sintered Snow
Snow & IceStrength of MaterialsSoil MechanicsUnconfined compressive strength of sintered snow as a power law in density, normalised to solid ice. It is an empirical fit with very wide scatter, not a law, and it leaves out the variable that matters as much as density does: how long the snow has been sitting undisturbed.
R-Value of a Snow Wall
Snow & IceHeat TransferThermodynamicsArea-specific thermal resistance of a snow wall, straight from its thickness and its density, with Sturm's conductivity fit folded in so you never have to look k up. It answers the question a shelter builder actually asks — how much wall is worth building — and nothing whatsoever about whether the shelter is safe.
Snow Gun Output Rate
Snow & IceHVAC & HydronicsTrades & ConstructionSnow production rate from the water flow a gun is fed and the density of the snow it makes. Guns are specified in gallons or litres per minute of water and hills are planned in cubic metres or acre-feet of snow, and this is the conversion between the two.
Snow Made in a Wet-Bulb Window
Snow & IceHVAC & HydronicsTrades & ConstructionHow much snow a given water flow actually puts on the ground over a night, once the water lost to evaporation and drift is taken off. THE FACT THIS PAGE EXISTS TO TEACH: snowmaking is gated on WET-BULB temperature, not on the thermometer. You can make snow at +2 °C if the air is dry enough, and you cannot make it at −1 °C if the air is damp.
Snow Volume from Water Volume
Snow & IceHVAC & HydronicsTrades & ConstructionHow much snow a given volume of water becomes, at whatever density the snow is made to. It is a mass balance and nothing more — the water does not change amount, only how much space it occupies — which is why the snow density on the bottom is the only interesting number in it.
Snow Water Equivalent (SWE)
Snow & IceWater & WastewaterThermodynamicsThe depth of water you would be left with if a snowpack melted where it lies — snow depth scaled by the ratio of snow density to water density. It is the number hydrology, irrigation and flood forecasting actually use, because depth alone says nothing about how much water is standing on the ground.
Snowpack Settlement (Viscous Compaction)
Snow & IceSoil MechanicsWater & WastewaterHow much a layer of snow densifies under a constant overburden, treating snow as a Newtonian fluid in compaction — Kojima's model, in the form land-surface schemes have used since Anderson wrote SNTHERM. It is the reason a snowpack is shallower in the morning than the depth board said last night, with the same water still in it.
Thermal Conductivity of Snow (Sturm 1997)
Snow & IceHeat TransferThermodynamicsEffective thermal conductivity of seasonal snow from its density alone, using the quadratic fit Sturm and colleagues published in 1997 from 488 measurements. This is the equation behind the fact that a snow shelter works: at 300 kg/m³ snow conducts about the same heat as softwood, and the air trapped between the grains is doing almost all of it.
Wet-Bulb Temperature (Stull 2011)
Snow & IceHVAC & HydronicsThermodynamicsWet-bulb temperature from dry-bulb temperature and relative humidity in a single closed-form expression, fitted by Roland Stull in 2011 to replace the iterative psychrometric solve. It is the lowest temperature evaporation alone can reach, which makes it the control variable for cooling towers, evaporative coolers, heat-stress limits and snowmaking alike.