Among the scattered showers and thunderstorms that moved across southern Wisconsin on Sunday, a few storms were strong enough to produce small hail. In particular, one storm that moved through the West Bend area in Washington County produced some interestingly shaped hail between about 515 and 530 pm. Two of our weather spotters sent us pictures of hail stones that appeared to have a generally spherical body and 1 to 3 spikes protruding from the body.
It is difficult to determine how hail stones get a shape like this, but it is likely due in part to hail stones colliding with each other and sticking together as they are growing. This is more commonly seen in larger hail stones that have a larger surface area to "catch" other stones while they are caught in the updraft of a storm.
When measuring these hailstones we measure the body part of the stone, not inclding the spikes. Several of these appear to be around 3/4" and one nearly an inch. Others are around 1/2".
This picture came to us from Adam in West Bend: (click to enlarge)
The two pictures below are from Steve, also near West Bend. (click to enlarge)
If you look closely at the spike on the left in the above picture, you can see one spike "inside" with another spike outside. This happens when a hail stone that had been falling gets caught back in an updraft and takes another trip up through the storm, catching another layer of super cooled water droplets.