<diacritize> That morning , shortly before 8 : 00 a.m . , Mount Pelee erupted , venting a searing mass of pyroclasts ash , cinders , obsidian , pumice , and superheated gas that ranged from 400 to 900 degrees Fahrenheit 200 - 500 C . <yor>That morning , shortly before 8 : 00 a.m . , Mount Pelée erupted , venting a searing mass of pyroclasts ash , cinders , obsidian , pumice , and superheated gas that ranged from 400 to 900 degrees Fahrenheit 200 - 500 C . 