Last week I found fluffy drifts on the sidewalks in my neighborhood. They’re the airborne seeds of London plane trees (Platanus × acerifolia), planted in Pittsburgh in the late 1800s because they’re tolerant of air pollution.
Then in the first warmth and light of spring the seed balls disintegrate and the seeds blow away. You’ll find drifts near American sycamores, too.
In March the trees are snowing.
(seed drift photo by Kate St. John; remaining photos from Wikimedia Commons, click on the images to see the original)