Snow sliding off solar panels and roof characteristics

I posted a photo of the snow having slid off the solar panels. We are fortunate to have a steep pitch to our roof and panels that aides snow sliding off. However, panels at the top right of the array do not have panels below them and have snow on the shingles blocking this snow from sliding. Note how snow has started to slide but has stopped [far right panels at top]. Much of the snow has slid off the panels to the left. The lower photo shows how far the snow can slide and be thrown away from the roof.
Though it is difficult to quantify, it seems that both mild and cold snow conditions result in snow sliding. Freeze-thaw cycles during the night and day can cause icing at the snow-glass interface and increase sliding resistance and physical binding of the snow to the panels.
Notice the relatively deeper snow on the lower roof of both houses. The combination of the lower pitch and the snow accumulation on the more sheltered lower rooves is quite evident. The snow on the lower roof is over 30 cm deep in spots. This would not be an ideal location for solar PV panels for good winter generation. The snow storm had wind blowing from the NW and has dumped snow on these SE facing rooves.