Summary:

## Initialization of Snow Layer

This section describes the initialization process for a new snow layer when there are no existing snow layers, but the snow depth (z_sno) is greater than or equal to 0.01 m after accounting for solid precipitation (q_sno).

Key points:

1. A new snow layer is initialized with the following parameters:
   - Thickness of the new snow layer (Δz_0) is set to the current snow depth (z_sno).
   - The depth of the new snow layer (z_0) is set to -0.5Δz_0.
   - The depth of the underlying soil layer (z_h,-1) is set to -Δz_0.
   - The temperature of the new snow layer (T_0) is set to the minimum of the freezing temperature (T_f) and the atmospheric temperature (T_atm).
   - The ice content of the new snow layer (w_ice,0) is set to the total snow water equivalent (W_sno).
   - The liquid water content of the new snow layer (w_liq,0) is set to 0.

2. This initialization process creates a new snow layer with the appropriate physical properties based on the current snow depth and atmospheric conditions.