19th century chronicles offer clues to mystery volcano
Meteorological records narrow down time and place of massive eruption that helped trigger decade of extreme cold
VOLCANIC AFTERGLOW Particles blasted into the atmosphere by volcanoes can create foggy, colorful effects in the sky, such as this purple twilight that followed the 1991 eruption of Mount Pinatubo in the Philippines.
Stephen F. Corfidi/NOAA-NWS Storm Prediction Center