I heard a woman on the radio today talking about getting ready to evacuate her house due to approaching forest fires. She said she was placing same irreplaceable items in her pickup truck - paintings and heirlooms, and locking up her family's important papers in a firesafe.
That reminded me of a conversation I had with a lady whose house did burn down in California (San Diego) four years ago. She also left important papers behind in a firesafe. She'd only had about five minutes warning before the fire took her house, so she can't be faulted. And when she returned to the pile of ashes that used to be her home, she found the fireproof safe intact and still locked. But when she opened it, as soon as oxygen hit the contents, everything crumbled. Apparently fireproof safes will keep the flames away, but the temperature will still reach several hundred degrees and bake everything inside until its brittle.
Her advice? - put all your important stuff (birth certificates, marriage certificates, deed to the house, passports, etc.) in a grab bag that you can get to in under a minute and take with you.