The Little Ice Age began in the late 13th century, scientists now posit, and lasted about 400 years. Some regions cooled significantly. A series of volcanic eruptions has become a leading culprit.
The eruption at Eyafjallajökull volcano in Iceland has been hugely disruptive to world travel. But as a volcanic event, it's barely worth mentioning.
Mount Redoubt, an active stratovolcano in the state's Aleutian Range, is twitching and belching like someone who just downed a case of Mountain Dew, signs that geologists say tend to precede an eruption.