It is of some interest to know roughly where the snow level in the San Gabriels is currently, and to what minimum elevation it typically might fall to during a storm. Snow on a trail can completely change one's hiking experience. Most people should not be hiking when there is general snow cover for a variety of reasons.
Navigation can be quite difficult when snow completely obscures a trail, leading to lost hikers.
Snow on steep slopes can create dangerous conditions, leading to hikers falling to their deaths. However, there is no such thing as the snow level, except perhaps immediately during a storm. After a storm, snow melts quickest on southern exposed slopes, and lingers longest in deep shaded recesses on northern slopes. What we define as the snow level in the plot below is the elevation above which one can fairly reliably find snow nearly everywhere in the San Gabriels. We generally determine this snow level from a visual inspection of the south side of the San Gabriels, combined with personal experience, webcameras and news and weather reports.