New flow is a shiny, silvery gray color, because none of its glass, which forms most of the rock, has altered chemically or physically. If the flow is less than a week old, scientists may feel substantial heat as we approach it or step onto it. Shimmering heat waves in the air above a recent lava flow may give it away, too. If the mapping doesn't begin until the flow is cool, it can be more difficult to recognize new flow from old flows. Scientists will look for other clues, including burned trees or brush, ash from the burned vegetation and subtle differences in color.
Scientists say that the law flows begin to revegetate quickly - meaning plants return to the area.
Even near flows only a few months old, tiny ferns can be seen sprouting where moisture collects.