One town where most of the people living there are being forced to evacuate. The problem, a giant ice jam threatening to wash away everything. Abc's neal karlinsky shows us what people in galena,... See More
One town where most of the people living there are being forced to evacuate. The problem, a giant ice jam threatening to wash away everything. Abc's neal karlinsky shows us what people in galena, alaska, are up against. Reporter: Right now galena is flooded, crushed by its ice. Pictures from the remote town show a 30-mile wall of the frozen river pushing over its banks and into homes. It's like having a glacier advance at you at six miles an hour. Fast water carrying big ice. That's a lot of momentum and when it hits a structure, the ice will always win. Reporter: A full 300 of the town's 500 hearty residents had to be evacuated by air. The cause is an ice jam on the yukon at a choke point where the river bends near galena. Emergency officials say it hasn't just caused flooding, but something they call ballistic ice, chunks theize of desks. You can have something form locally and start flooding instantaneously. Reporter: While flooding isn't unusual this time of year what's happening in galena is the worst they've seen and water levels aren't expected to drop until the ice begins to break up on its own. For "good morning america," neal karlinsky, abc news, seattle.
This transcript has been automatically generated and may not be 100% accurate.