Russia's Bezymianny volcano blew itself apart 69 years ago. It's now almost completely regrown.

A restless Russian volcano sent an ash cloud 32,800 ft feet (10 kilometers) into the air in late November in an eruption that may bring the mountain closer to its original height.

The Bezymianny volcano is a dramatic, cone-shaped stratovolcano on the Kamchatka Peninsula in the Russian Far East. It blew itself apart in 1956, but a 2020 study found that it has nearly grown back — and eruptions like the one that created an ash plume on Nov. 26 are the reason. That study found that the mountain should achieve its pre-collapse height between the years 2030 and 2035.

Seven decades ago, Bezymianny towered at least 10,213 feet (3,113 meters) above sea level. Then, on March 30, 1956, a massive eruption blew out the slope of the volcano, collapsing the summit and turning the cone-shaped mountain into a horseshoe-shaped stone amphitheater.

Almost immediately, though, the mountain started to reform, starting as a lava dome perched in the midst of this amphitheater. Over the years, the Institute of Volcanology and Seismology in Kamchatka, part of the Russian Academy of Sciences, has monitored the mountain's growth with fieldwork, web cameras and observation flights. A series of photographs taken from flights between 1949 and 2017 shows that the volcano has nearly reached its previous height, the researchers reports in 2020. Between 1956 and 2017, the researchers found, the mountain added 932,307.2 cubic feet (26,400 cubic meters) of rock per day, on average, the researchers found.

"The most surprising thing was the fast growth of the new volcanic edifice," study co-authors Alexander Belousov and Marina Belousova, both volcanologists at the Institute of Volcanology, told Live Science in an email.

The volcano now produces a couple of explosive eruptions a year, on average. The late-November event featured not only a billowing ash cloud, but also hot avalanches of gas and rock known as pyroclastic flows, Smithsonian's Global Volcanism Program reported Dec. 2.

As the volcano reaches its original height, the stability of its slopes is an important question, Belousov and Belousova told Live Science.

"It is known that similar edifices located inside horseshoe-shaped craters can experience one more large scale collapse and, as a result, a large scale explosive eruption," they said.

The flyover images reviewed in 2020 showed that the volcano not only sends out explosive clouds of ash and gas, but that it grows by what scientists called effusive eruptions: non-explosive flows of lava. The first of these was visible in 1977. Over time, this lava has become less rich in the mineral silica and less viscous, or goopy. Layers of this effusive lava have built up to turn Bezymianny back into a cone-shaped stratovolcano.

Researchers are still monitoring the mountain from the ground as well as by satellite, Belousov and Belousova said. Though each volcano has its own trajectory, there are many volcanoes around the world that have experienced collapse and regrowth, such as Mount St. Helens in the U.S.

"The collected dataset is very important because the obtained knowledge allows volcanologists all over the world to make long-term forecasts of the behavior of different volcanoes which experienced large-scale collapses in their history," the researchers said.