Asteroids are flying past the earth more often than usual

We've had an "eyebrow-raising" number of close-shaves with asteroids in the past month, according to astronomers. 
A total of four asteroids have buzzed past the earth this year already, with the most recent one flying between the earth and the moon earlier this week.
The number of close shaves in such a short space of time has “raised eyebrows,” according to the Slooh observatory.

Asteroid 2017 BS32 came within about 100,000 miles of us this week, and was roughly the size of a bus.
The number of sightings in such a short space of time has forced astronomers to wonder if the asteroids are part of a bigger fallout from larger asteroids that have broken up.
Paul Cox, astronomer at Slooh, told CNET that this theory has fallen through as the asteroids turned out to not be related.
They then looked to weather or seasonal changes for a possible explanation, and found nothing.