http://images.nationalgeographic.com/wpf/media-live/photos/000/247/cache/pompeii-victim_24759_600x450.jpg
"The damage on the ancient bones, showing micro-cracks on the surface and recrystallistaion of the interior bone structure, are signs of thermal modification. Comparing these bones with the observations made on modern bones, heated in experiments, the researchers were able to determinate a temperature range inside the surge that killed the people, at least 500-600°C at Oplontis and Herculaneum, and 300-250°C at Pompeii.
The temperature at Herculaneum and Oplontis was enough to vaporize the flesh of the victims, so that the ash could embed the skeletons, in Pompeii, due the cooler temperatures, the bodies remained intact and were preserved inside the volcanic sediments. After decomposition of the organic material a void remains, that today can be filled with plaster to form a cast of the unfortunate victims."
http://blogs.scientificamerican.com/history-of-geology/2012/05/03/geology-scene-investigation-death-by-volcanic-fire/
Certainly not out of the question.