Mount Rainier looms over Seattle like a sleeping giant with really bad insomnia—the kind where you’re never quite sure if it’s actually resting or just pretending. This 14,411-foot stratovolcano last erupted around 1450, but don’t let that lull you into thinking it’s retired. The thing produces more lahars—those cheerful mixtures of volcanic debris and water that barrel down mountainsides at highway speeds—than almost any other volcano in the lower 48.
When Active Doesn’t Mean What You Think It Means Anymore
Here’s the thing about Kilauea in Hawaii: it’s been erupting almost continuously since 1983, which makes calling it “active” feel like calling the ocean “slightly damp.” The 2018 eruption alone destroyed over 700 homes and created enough new land—875 acres of it—to make real estate developers weep with envy and frustration. You can actually walk on rock that’s younger than your smartphone. The current eruption cycle that began in December 2020 fills Halema’uma’u crater with a lava lake that acts like Earth’s mood ring, constantly shifting and glowing.
Watching lava flow into the ocean creates its own weather system.
The One That Reminds Us We’re All Just Renting Space Here
Mount St. Helens blew its top on May 18, 1980, and instantly became the poster child for why we should respect geological forces. The eruption released 24 megatons of thermal energy—roughly 1,600 times the Hiroshima bomb—killed 57 people, flattened 230 square miles of forest, and dropped the mountain’s height by 1,314 feet. But wait—maybe the most unsettling part is how quickly nature decided to move back in. The blast zone now hosts thriving ecosystems of plants and animals that somehow found the moonscape appealing. You can hike to the crater rim and stare into what looks like Earth’s unfinished basement, complete with a lava dome that’s been growing since 2004 like some kind of geological tumor.
The Johnston Ridge Observatory sits just five miles from the crater, named for volcanologist David Johnston who radioed “Vancouver! Vancouver! This is it!” moments before the blast killed him. That’s about as dramatic as last words get.
Lassen Peak and the Volcano Nobody Remembers Until They Visit
Lassen Peak in Northern California erupted over 150 times between 1914 and 1917, making it the most recent volcanic eruption in the contiguous United States before St. Helens stole its thunder. The 1915 eruption shot a mushroom cloud seven miles into the atmosphere and created the Devastated Area—which sounds like a metal band name but is actually a three-mile stretch of terrain that got absolutely hammered by a pyroclastic flow. Bumpass Hell, a hydrothermal area within Lassen Volcanic National Park, bubbles away at temperatures exceeding 200°F and smells like Satan’s chemistry experiment. It’s named after Kendall Bumpass, who discovered it in the 1860s and promptly broke through the crust, severely burning his leg. The leg later required amputation, proving that nature has a dark sense of humor about naming conventions.
Turns out you can boil an egg in the thermal features here, though the park rangers get really annoyed when you try.
Yellowstone and the Supervolcano Everyone Loves to Catastrophize About
The Yellowstone Caldera sits atop a volcanic hotspot that’s produced three massive eruptions: 2.1 million years ago, 1.3 million years ago, and 640,000 years ago. Each eruption was thousands of times more powerful than Mount St. Helens, covering half of North America in ash and fundamentaly altering global climate. The caldera measures 30 by 45 miles—large enough that you can stand inside it without realizing you’re in a volcanic crater. The ground rises and falls by inches per year as the magma chamber beneath breathes like a sleeping dragon. Old Faithful erupts every 90 minutes or so, shooting up to 8,400 gallons of boiling water up to 180 feet into the air, which makes it possibly the world’s most punctual geological feature.
Scientists estimate the chance of a supereruption in any given year at about 1 in 730,000. Those are better odds than winning the lottery, but the consolation prize is considerably worse.
The Norris Geyser Basin contains Steamboat Geyser, the world’s tallest active geyser, which can shoot water over 300 feet high when it feels like performing—though it might wait three days between eruptions or three years. Nobody really knows its schedule, which makes Steamboat the geological equivalent of that friend who shows up to parties whenever they feel like it and always makes a scene.
