Richard+Ho

1. Cleveland Volcano is a 5,676-foot mountain that rises above the Aleutian Islands in Alaska. Mount Cleaveland is one of Alaska's active volcanoes.

2. Lava domes can become unstable when they grow big enough and a dome collapse could lead to an explosive release of ash and volcanic gasses.

3. On September 22, the lava dome had grown to 65 feet below the crater rim. This has increased the possibility of an explosive event.