There are no clear warning signs for eruptions like the Taal volcano

USA Today quotes Tracy Gregg, regarding the Taal volcano in Philippines which erupted Sunday forcing thousands of residents to flee. Gregg discussed the difficulty in predicting such eruptions. “The truth is that we have no good precedent for how such a large volcano gears up into a cataclysmic eruption," she said. "We know that such eruptions occur ... but we don't know what specific advance signs such a gigantic eruption would give us because we've never witnessed one.”