reporter: before-and-after satellite images show the devastation in tonga. volcanic ash is covering entire communities, homes, trees, roads blanketed. neighborhoods, unrecognizable. the new zealand defense force sent a reconnaissance flight to assess the damage. the runway at the airport is partially covered, meaning humanitarian flights are currently impossible for a population of more than 100,000. saturday s eruption of an underwater volcano triggered a tsunami. the prime minister says waves of up to 15 meters hit parts of the tongan coastline. tsunami waves felt thousands of miles away in hawaii, peru, japan, and the west coast of the united states. whilst the damage is is horrifying, um, we were fearing much worse. it was so powerful that eruption. reporter: believed to be the most powerful volcanic eruption in more than 30 years, the true extent of the damage is not yet known. new zealand and australia have