I was with my in-laws in the backyard of a house. The yard was large, green lawn stretching for acres, but the immediate half acre of the backyard was edged with giant deciduous trees. The trees had few branches, primarily upwards stretching, rather than outwards, and had no leaves. They didn't seem unhealthy, just leafless as in winter. The sky was light grey, clouded over.
We were just standing there, when a tree at the far right corner of the yard crashed to the ground towards the end of the yard we were in (though in a straight line, parallel with the edge of the yard, not diagonally, towards us). It didn't quite reach the house-end of the yard. Then, one by one, each of the trees lining the back edge of the yard crashed down towards the front/house end. They crashed with enormous force, and branches cracked and shot up into the air. None came close to hitting us or the house.