When lava meets ice, most people assume there will be some type of explosion. Probably because of the drastic temperature difference between lava and ice. But that doesn't actually happen. The thing that happens is that the lava forms a blanket of super-heated steam over the ice surface, and that minimizes the frictional force that would normally be between the ice and the lava. That's why the lava can flow over the ice without having to dig right through it.
The researchers did this experiment a few times to get a better understanding of how lava flows interact with snow and ice at real volcanoes. And they found that different types of lava flow differently with snow and ice, which can have a big impact on communities living near ice-covered volcanoes.
For example, jagged blocky "a'a" lava flows interact with snow and ice differently than smooth-flowing pahoehoe lava. That's why it's important to understand these interactions. And the good news is, that if you were to fall in contact with lava for a very brief period of time (say, a few seconds) you would only experience a painful burn, and not a deadly explosion. The longer the lava was in contact with you, though, the worse your burns would be. So, keep your distance if you ever see a volcano erupting! And for a little science fun, try dropping dry ice into lava! It will melt the ice, but bubbles of super-heated steam will also form in the lava.