Scientists monitoring Washington volcanoes say the noise from melting glaciers is making their work more difficult.
Scientists who study volcanoes say the first sign that an eruption is imminent is often a swarm of tiny earthquakes -- so small that humans don't feel them and they register near zero on the Richter scale.
But to an observant scientist, these tiny movements are a sign that molten rock is beginning to move.
The problem, said University of Washington grad student Kate Allstadt, is that on Mt. Rainier in particular, the mountain isn't the only thing making noise. The glaciers on the mountain crack and pop, creating tiny quakes of their own. The worry is that when the glaciers become more active, all that popping and cracking can mask the true signs of an eruption.
"The small earthquakes, and the behavior of small earthquakes, is what we really look at to monitor the volcanoes," said Allstadt.