Can you see the small white dots, like dotted Swiss (a kind of fabric) from the 50s? We’ve seen them and can’t figure out where they come from. They are powdery and dry and about 1/2 inch in diameter at the most. They usually appear in clusters of 50-100, sometimes dense around an object, sometimes more spread out.
So today we got out our intellectual detective kits and discovered that they don’t appear near the cliffs. They are often found near the tracks of the patrolling lifeguard jeep and sometimes near footprints.
Conclusion, to be tested with further evidence on other walks: they are kicked up by the motion of the tires/wheels on lighter, dryer sand, and are sprayed outward onto the darker sand. They also seem to form around footprints of runners (deeper footprints), which probably also ends up with sprays of lighter sand.
Any other ideas? They don’t seem to be creature-related, aren’t ant-hills, are very thin and ethereal (nothing under them when you touch them, no bug or hole) and perhaps only 10 or 20 crystals of sand deep.