Did Mount Rainier Erupt? Webcam Footage Sparks Speculation About Volcano

A video showing a white plume ominously moving over Mount Rainier on Wednesday sparked concern that the active volcano in Washington state was about to erupt.

Mount Rainier National Park officials quickly took to Twitter to dispel the rumor.

"Mount Rainier is NOT erupting," the tweet said. "We have looked at the cloud that has caused concern from multiple webcams and have determined that it is a lenticular cloud. In addition, the USGS reports no indications of unusual seismic activity."

A video showing clouds that looked suspiciously like a potential eruption was posted on KOMO meteorologist Kristin Clark's Twitter.

"Mt. Rainier appears to be venting," the tweet said.

In the video, a man can be heard saying, "It is, it is definitely moving," in reference to what was later determined to be clouds at the volcano's peak.

AccuWeather described lenticular clouds as clouds that "have been regularly confused for UFOs throughout history due to their smooth, round or oval lens-shaped structure." The clouds are common, especially near mountainous areas. They can be singular clouds or stacked like pancakes.

Even though Mount Rainier has not had a "significant" eruption in the last 500 years, the United States Geological Survey (USGS) calls the volcano potentially the most dangerous one in the Cascade Range. The USGS attributes the danger to the volcano's great height of more than 14,400 feet, its frequent earthquakes, an active hydrothermal system and an extensive glacier mantle that includes 25 major glaciers that have five times the snow and ice as all other Cascade volcanos combined.

"If only a small part of this ice were melted by volcanic activity, it would yield enough water to trigger enormous lahars (debris flows and mudflows that originate on a volcano)," the USGS said on its website. "Mount Rainier's potential for generating destructive mudflows is enhanced by its great height above surrounding valleys."

KUOW, a Seattle NPR station, reported in 2018 that if Mount Rainier were to erupt, it would sound like "a rocket launching." Reports said that although lava would stop flowing near the national park's edge, it could cause avalanches and flash flooding.

The National Park Service said it is uncertain if Mount Rainier will erupt again. In a 1986 note published on its website, the NPS said there may have been volcanic activity on Mount Rainier in the 1800s. It quoted an 1873 story by the Washington Standard that reported: "The Dispatch says that last Sunday afternoon about 2 o'clock a slight shock of an earthquake was felt at Seattle, and at 4 o'clock clouds of smoke were seen pouring from the highest peak of Mount Rainier. The smoke was seen until nearly dark when clouds shut down upon the mountain hiding it from view."

The NPS said there were at least 14 eruptions reported on Mount Rainier between 1820 and 1894.

"Since geologists discovered only a light layer of ash from that time, most of the 'eruptions' which people reported seeing were probably only dust clouds rising from large rockfalls or the cloud cap frequently seen over Mount Rainier," the NPS site said.

The NPS said scientists are carefully monitoring the volcano.

"Yet, no one knows for sure when, and if, it will wake up from its dormancy. Hopefully, the complex mysteries of volcanoes will diminish as geologists gain more insight through their study of Mount St. Helens," which had a sizable eruption in 1980.

Newsweek reached out to Mount Rainier National Park for comment.