From BearWiki
Claim: Hot lava does not set boots on fire like that.
Tourist walking on active flow with newly crusted surface. Note that she was wearing regular sneakers with no apparent flames. January 12, 2003.
Hawaii Volcano Observatory photographer in green shirt after crossing active lava flow on newly crusted surface. Surface is still near the temperature of liquid lava (2000 deg F) but is also extremely hard. I have thrown huge rocks at it and they just bounce off. In addition, lava is much denser than water, so it would tend to float any person on top rather than allow him to sink. The element of danger is still there should one trip and fall on the hot surface. Photograph taken on July 19, 2002 on the first day that the Mother's Day Flow reached the Pacific Ocean.
HVO photograper in green shirt after I have crossed the active lava flow from the other side. Bottoms of boots are hot to the touch and feet feel slightly warmer, but no significant damage to the soles of the boots. There is a time delay of several minutes before heat from the sole reaches the feet, so it will not become unbearably uncomfortable if one reaches a cooler surface to cool down. July 21, 2002.
I have personally walked on very hot lava just minutes after it crusted over. My boots have never burst into flames. The rubber soles will start melting and get slippery, but never burn. It looks like somebody soaked his boot with lighter fluid and threw in a match.(Reference: Volcanochaser 14:28, 14 August 2007 (CDT) / )
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In "More Kilauea inconsistencies and bad advice", Lumbee makes the same observation:
Your shoes would ignite like his only if the rest of your body was also burning. Meaning, that kind of heat is impossible to come close to. Can you just walk into a fire? I've hiked across mile wide sections of flowing lava and yes, your feet get really hot but, your shoes glue starts melting and smoking long before they burn. Even at that point your skin is starting to burn.
[edit] Analysis
