Hello.
I noticed a potential inconsistency regarding the snow depth product documentation on::
The documentation states that:
“Green shades relate directly to model assumptions regarding proportion of the ground assumed to be covered by snow - when the diagnosed depth is less than 10cm the model assumes that there is only partial cover, and surface fluxes are treated accordingly. Thus the green shades (< 10cm) aim to signify, visually, that some of the underlying vegetation is showing through. For depths above 10cm a total cover is assumed (so no green hues).”
However, in the Physical Processes documentation of the IFS cy49r1:
Equation 8.2 of the Page 153 describes the snow cover c_sn as depending explicitly on snow depth (S_tot/rho_sn,eq) AND snow (whole) layer equivalent density rho_sn,eq. Following this equation 8.2, the minimum snow depth leading to a 100 % snow coverage (c_sn=1), assuming a snow layer equivalent density of 300 kg/m³, is 20 cm (which indeed gives c_sn=0.99), and not 10 cm as indicated in the documentation of the above mentioned snow depth charts.
This 10 cm snow depth threshold seems to come from a previous version of the above mentioned relationship in a older IFS cycle:
See Equation 8.2, page 129.
So could you clarify which value should be considered authoritative for interpreting the snow depth charts? Or may be I missed something? 
Thank you for your time and guidance.
Best regards,
Fabian Debal,
Royal Meteorological Institute of Belgium.