From the FCS Book of Little-Known Facts (snowflakes on water)

When snowflakes hit water they create a screeching sound too high for humans (but not some sea animals) to hear. When a flake hits the water, an air bubble is released that oscillates in the 50-200 khz range well above a human’s range. Snow hitting water can increase underwater sound by 30 db.

There is never a time
to stop learning new things