I give Bovista as a highly plausible genus for this sighting, but not guaranteed to be correct. These are still immature. One or more species of Bovista are common small puffballs in our area. They are likely to appear at many times of the year, during warm days after rain. At times (especially in summer, when days can get quite dry and hot after a spot of rain) you may see many of these, still immature, split in the heat and so fail to get to the sporing stage.