@pkofman
In Meteogram the accumulation of rain or snow is that predicted during the previous 3 hours.
If you want to know the accumulated snowfalls during several days, they are shown in the New snow layer.
FC7AEFC3-BB7B-4FF3-AF52-C2CA11152C29.jpeg
By the way this accumulation is not the depth of snow laying on the ground, which results of snowfall, self compaction and melting.
See Snow depth layer.