I have a huge oak tree in my front lawn that branches over my driveway where we park the cars.  When we go out, we have had to cover our heads for the past few days because it is literally raining acorns.  According to the Farmer Almanac, it seems this is a natural predictor of a really bad winter.  I'm thrilled.

According to Northwoodlands.org:

The synchronous, periodic production of large seed crops within tree populations is often called “masting.'

The article also goes on to say that it was folklore that when many acorns fall, it's a predictor of a bad winter, but there is a scientific reason for it.

It's a defense mechanism for the tree.  Basically, every two or three years, the tree will produce an over-abundance of acorns so the "acorn predators" will be satisfied and leave some of the acorns on the ground to reproduce and keep the species healthy.

Now I have an explanation of why I have so many squirrels in my yard.   Since I don't have inside pets, I rather like them, but I wish they could clean up these acorns a little faster.  They are everywhere.