A'a (jagged) lava meets Pahoehoe (smooth) lava near Kilauea crater, Big Island, Hawaii. Pahoehoe lava flows smoothly like water or molasses. A'a lava tumbles in the form of small rocks with very jagged sharp edges. The rocks are very lightweight, as opposed to pahoehoe that is extremely dense, and a'a rocks tend to pile up on each other with a lava front that might be a few feet to 40 or 50 feet high of tumbling red hot sharp rocks.