hoehoe: Wikipedia says:
The very hot lava flows under a horizontal solidifying crust then that constantly raises in lava back or slipping apart and leaves lava pillow.
This is in the background behind us A'a oddly we are but on Pahoehoe. Pretty rough stuff, what may be one of the reasons pretty sharp why people A'a name have taken over the outcry was probably, if someone there injured has 🙂
Also, there's a Wikipedia article:
During the solidification of the melt flow, breaking the crust and leaves a surface that is riddled with sharp-edged, irregularly shaped lumps and floes.
The AA lava flows more slowly compared to the Pahoehoe lava and is cool; often, it is located in the lower part of low-viscosity lava flows because due to outgassing and cooling increases the toughness. At the end of the current forms a steep front.