Duckweed hurricane

If this were a screenshot from the Weather Channel website, it would be accompanied by lurid red and black letters and flashing warning lights, to say nothing of an on-location update from disaster master Jim Cantore. But the image is actually an after-the-storm shot, and though it looks like a satellite view of a hurricane, the "pixels" are nothing more than individual duckweed plants that are being sucked into the vortex of a mini-whirlpool  which magically formed by the edge of the millpond waterfall. The cause of the current was all the rain we had yesterday, and it had one interesting impact on the pond, the north edge of which was choking in duckweed. The whirlpools—there were several—acted like vacuums and cleared away all that green. The duckweed disappeared downstream.