A reader sent me this vintage 1970s postcard of Hot Rock. It is one those unusual features in Lassen Volcanic National Park.

Hot Rock was of many remnants of the Lassen Peak eruption of May 19-20, 1915. First, there was a blast dacite lava and with great force that created boulders, large and small. But, there is more. The lava melted the heavy snow, creating what would became known as The Great Mudflow. When B.F. Loomis visited  this site on May 21, what became the Devastated Area, he noted this large boulder, was still hot, and hence its name. Schaffer. (1981) estimated that at time of the eruption the rock could have exceeded 1600F. It should also be noted, that looks can be deceiving.  The rock is like an iceberg. It is estimated that the 300-ton boulder is buried under of twelve and eighteen feet of mud in its final resting place.feet, so one only sees a small portion of the boulder.

Tim