Yeah - I think the biggest factor is that there was a tremendous amount of convection in that band so you had a lot of latent heat release doing some funky things to the thermal profile. When we had 1/4 mile +SN in Groton and reports of rain and hail on the east side of the mega band we knew something pretty wild was happening.
The "asteroid ice" that fell was more like hail than sleet - plenty of riming and also some legit hail characteristics around the updrafts.