Snow interacts with its environment in many ways, is constantly changing
with time, and thus has a highly heterogeneous spatial and temporal
variability. Therefore, modeling snow variability is difficult,
especially when additional components such as vegetation add complexity.
To increase our understanding of the spatio-temporal variability of snow
and to validate snow models, we need reliable observation data at
similar spatial and temporal scales. For these purposes, airborne LiDAR
surveys or time series derived from snow sensors on the point scale are
commonly used. However, these are limited either to one point in space
or in time. We present a new, extensive dataset of snow variability in a
sub-alpine forest in the Alptal, Switzerland. The core dataset consists
of a dense sensor network, repeated high-resolution LiDAR data acquired
using a fixed-wing UAV, and manual snow depth and snow density
measurements. Using machine learning algorithms, we determine four
distinct spatial clusters of similar snow depth dynamics. These clusters
are characterized and further used to derive daily snow depth and snow
water equivalent (SWE) maps. The results underline the complex relation
of topography and canopy cover towards snow accumulation and ablation.
The derived products are the first to our knowledge that provide daily,
high-resolution snow depth and SWE based almost exclusively on field
data. They are therefore ideally suited for the validation of
distributed snow models. Our approach can be applied to other project
areas and improve our understanding of the spatio-temporal variability
of snow in forested environments.