Images of the Northern plain on Mars have revealed up to 1500 km long lava flows. The low density of impact craters on the lava flows implies that these lava flows were formed during the most recent volcanic activity on Mars. Estimates of the ages of the flows are controversial but generally between 10 and 100 Myr. Parts of the lava flows show smooth kilometer-sized plates that appear to have rafted on the moving lava flow. We have found a terrestrial analogue with similar features, the Burfellshraun lava flow in Northern Iceland. This is the only known lava flow on Earth where kilometer-sized rafting plates are observed and constitute the dominating feature. Using a combination of airborne remote sensing data and field observations we have studied the emplacement and physical properties of the flow. On the basis of our observations we have reconstructed the sequence of events that led to the disruption of the lava surface. Our observations show that a ~45 km2 lava lake, holding about 0.7 km3 of lava, catastrophically collapsed releasing a flood of lava. During the collapse the crust of the lava lake was broken into plates up to a kilometer in width and a few meters thick that floated downstream for almost 10 km.