Mount Rainier is considered an active volcano and has not had a significant eruption in the past 500 years. However, it is potentially the most dangerous volcano in the Cascade Range due to its height, active hydrothermal system, frequent earthquakes, and heavy glacier cover.

Mount Rainier is an active stratovolcano 45 miles southeast of Tacoma and 60 miles south-southeast of Seattle. Its last eruption was "a light dusting of ash" in 1894, the USGS said in a report. Large eruptions haven't occurred for more than 1,000 years.

The U.S. Geological Survey said it and other agencies were monitoring the situation and would issue additional alerts "as needed."

While considered an active volcano, Mount Rainier hasn’t erupted in at least a century, possibly much longer. The U.S Geological Survey said there was no physical evidence to confirm a reported 1894 eruption, nor eruptions earlier in the 18th and 19th centuries. The last eruption with strong geologic evidence happened about 1,000 years ago.