This type of lava becomes very viscous and sticky which makes it very hard and dangerous to walk on. When moving the crust breaks up and cools to become jagged but is still a solid with a dense inside. With this type of flow, there is a high eruption rate, and produces lava fountains. In an A'a flow, more cooling takes place, so the lava becomes much thicker than it would be in a Pahoehoe flow. This is a common type of lava found on the caldera floor.
Pahoehoe lava is very fluid as it flows.
Pahoehoe and a'a lava have the same chemestry. A Pahoehoe flow can turn into an a'a flow when the the temperature rises. Pahoehoe flows are what almost always make lava tubes, such as Thurston lava tube. Pahoehoe flows have a very low eruption rate. There is little cooling, so therefore the lava is still hot.