44 Fun Facts About Lassen Volcanic National Park

Lassen Peak is the southernmost active volcano of which mountains?

Cascades. The chain's southern end has crept north through time: three million years ago its last active volcanoes stood nearly 20 miles south of Lassen Peak.

Lassen Peak is one of the world's largest examples of which type of volcano?

Plug dome. Its lava was too stiff to flow away and piled up over the vent into a steep mound; the other three types all stand elsewhere in the park.

What did visitors report about the 30-ton boulder swept down by Lassen Peak's 1915 mudflow?

It stayed hot to the touch. The boulder had sat in the volcano's vent before the mudflow carried it down, and it has been called Hot Rock ever since.

Which taller volcano stands north of Lassen Peak?

Mount Shasta. Eruption after eruption built it to more than 14,000 feet, while Lassen Peak, at about 10,450 feet, rose in a single short burst.

What supplies the heat for Lassen's volcanoes?

An ocean plate sinking under the continent. As the slab descends off the Northern California coast it generates the magma that feeds the whole chain of volcanoes north to British Columbia.

Which president designated Cinder Cone and Lassen Peak as separate national monuments in the early 1900s?

Theodore Roosevelt proclaimed the two monuments in May 1907; after Lassen Peak began erupting seven years later, Congress joined them into a single national park.

What name is still given to the slope of Lassen Peak swept bare by its eruptions of May 1915?

Devastated Area. A mudflow and then a blast of hot ash and gas flattened about three square miles of forest, though trees have since grown back over much of it.

Lassen Peak and which other volcano were the only two in the contiguous US to erupt in the 20th century?

Mount St. Helens. Its 1980 blast was the range's first eruption since Lassen fell quiet, and it prompted geologists to step up their watch on Lassen and its neighbours.

Why was nobody killed when a 1915 mudflow from Lassen Peak swept away homes on Hat Creek?

Neighbours raised the alarm. Homesteaders warned one another as the flood came down the creek in the night and scrambled uphill; several houses were destroyed, but everyone escaped.

Who took the best-known photographs of Lassen Peak's eruptions?

Benjamin F. Loomis. His glass-plate photographs of the eruptions gripped the nation and helped win support for the park, and he later built and gave it the museum that still shows them.

Lassen Peak rose on the flank of which older stratovolcano, since worn down to a ring of lesser peaks?

Mount Tehama. After it fell silent, hot acidic water rotted its lavas and glaciers carted the rubble away, leaving Brokeoff Mountain and Mount Diller as stumps of its flanks.

Roughly how long ago did Lassen Peak rise?

About 27,000 years. The peak shot up within a few years, then Ice Age glaciers ground at it for thousands more, leaving its slopes draped in broken rock.

What is Lassen Volcanic's largest hydrothermal area, with boiling mudpots and roaring fumaroles?

Bumpass Hell. It sits where steam from the park's underground reservoir of boiling water escapes most strongly, and its Big Boiler vent has been clocked at 322 °F.

What befell the cowboy whose name one of Lassen's boiling thermal basins still bears, on a visit there in 1865?

He lost a leg. Bumpass broke through the thin crust over a boiling mudpot while guiding a newspaper editor, and the scalded leg had to be amputated.

Which roadside geothermal area between Lassen Peak and Brokeoff Mountain sits near the core of a long-eroded volcano?

Sulphur Works. Its acid steam has cooked the old volcano's hard grey lava into soft red, yellow and buff clays, and the ground there is still being remade.

What dated Cinder Cone's only eruption to the 1600s?

Tree rings. Rings in nearby pines point to 1666 as the year, and a willow already full-grown near the summit in 1853 gave the lie to prospectors' tales of an 1851 blast.

What are Lassen's Fantastic Lava Beds?

Lava flows from Cinder Cone's base. The lava broke out at the foot of the cone instead of the summit, and it still looks so fresh that people long took it for only a few decades old.

Where does the water in Lassen's boiling pools and steam vents come from?

Rain and snowmelt seeping underground. Deep down it meets hot rock beneath Lassen Peak, boils, and rises again as the steam that drives every mudpot and fumarole in the park.

Manzanita Lake in Lassen Volcanic formed a few centuries ago when what happened?

A rock avalanche dammed a creek. Part of a young volcanic peak nearby collapsed, and the debris ran four miles, far enough to climb 400 feet up the mountain opposite.

Which national scenic trail passes through Lassen Volcanic National Park on its route from Mexico to Canada?

Pacific Crest Trail. Its 2,650 miles follow the mountain crests from border to border, and through-hikers cross Lassen by way of Warner Valley, past the park's boiling springs.

Which volcanic feature just north of Lassen Peak formed only about 1,100 years ago?

Chaos Crags. They grew in the last large eruption in the Lassen area: blasts of pumice and ash, then six steep mounds of stiff lava, parts of which collapsed into fast flows of hot ash.

Peter Lassen, the park's namesake, was a blacksmith from which country?

Denmark. Lassen guided settlers past the peak that took his name, but the emigrant trail he blazed was so punishing that wagon trains gave it up within a few years.

Which Native people, who wintered along Hat Creek, moved into the north of today's Lassen Volcanic National Park each summer?

Atsugewi. Deep snow made the high country a summer camp only; the tribe wintered in the Hat Creek valley and is today one of the eleven bands of the Pit River Tribe.

The park's Kohm Yah-mah-nee Visitor Center takes its name from which language's word for Lassen Peak?

Kohm Yah-mah-nee means 'snow mountain' in Mountain Maidu, the language of the people whose homeland took in the park's southern slopes; the centre opened in 2008 near the southwest entrance.

Which 1851 pioneer wagon route to the Sacramento Valley was cut through today's Lassen Volcanic National Park past Cinder Cone?

Nobles. William Nobles pioneered the shortcut in 1851, and wagon trains soon abandoned Peter Lassen's longer, harder trail for it.

Which American fur trapper is recorded as passing near Lassen Peak in 1828?

Jedediah Smith. He skirted the peak on a trek up the Sacramento Valley towards Oregon, three years before Comanches killed him on the trail to Santa Fe.

What operated beside Lassen Volcanic's southwest entrance until the early 1990s, where the main visitor center now stands?

A downhill ski area. Lifts ran on the slopes there for decades, and when the old ski chalet was pulled down in 2005 the new visitor center took its place.

Up to how deep is the snow crews clear from Lassen's main park road each spring?

About 40 feet. The snowpack on the road's highest stretches can lie that deep, which is why the road sometimes stays shut until July.

Lake Helen is named for a painter who in 1864 became the first white woman known to do what?

Climb Lassen Peak. Helen Tanner Brodt and her husband joined pioneer Pierson Reading's party to the summit, and Reading named the lake below it after her.

Which of California's rarest mammals has one of its last known strongholds around Lassen Peak?

Sierra Nevada red fox. Dense fur on its toe pads carries it over deep snow, and it is so scarce and its range so rugged that biologists have struggled to study it since the 1930s.

Which 2021 wildfire burned about 69 percent of Lassen Volcanic National Park?

Dixie. The fire entered the park near Juniper Lake on August 5, 2021 and scorched about 73,000 of its 106,000 acres; the scar of a 2012 fire helped slow it.

Which town houses Lassen Volcanic's headquarters, evacuated during the 2021 wildfire?

Mineral. When the fire closed in during August 2021 the town was ordered out and the headquarters moved to Redding, and staff began returning about a week later.

Which historic guest ranch in Warner Valley lies inside Lassen Volcanic National Park?

Drakesbad. Its spring-fed pool is the one place in the park where the volcanic waters are safe to bathe in; everywhere else they are too hot or too acidic.

Despite its name, what is Lassen's Terminal Geyser really?

A steam vent in a creek. Cold stream water runs over the vent, and the steam spurting up through it only looks like a geyser.

Which hamster-sized relative of the rabbit lives among Lassen's high rock piles and dries 'haypiles' of grass for winter?

American pika. It stays active under the snow all winter, living on the grass it dried in summer, and rangers watch it as an early warning of a warming climate.

Congress gave most of Lassen Volcanic which status in 1972?

Wilderness. The designation keeps roads and permanent buildings out, so most of the park can be reached only by trail.

What is Lassen Peak made of?

Dacite. The lava is rich in silica and very stiff, and a tongue of it that oozed over the summit rim in May 1915 can still be picked out on the peak today.

What threat level does the USGS assign to Lassen in its national volcano assessment?

Very High. The ranking weighs how violently a volcano erupts against who lives in its path, and a repeat of 1915 would now threaten far more people than the few homesteaders of the day.

Which bird plants most of Lassen's timberline whitebark pines, by burying seeds for winter and leaving some uneaten?

Clark's nutcracker. The pine's cones never open on their own, so nearly every seedling grows from a cache that a nutcracker buried and never came back for.

Peter Lassen, namesake of the park, became a citizen of which country in 1844 to secure a vast California ranch?

Mexico. California was still Mexican territory, and its governor granted Lassen the 22,000-acre Rancho Bosquejo, where he laid out a town in the hope of drawing emigrants.

Which Lassen lake formed when lava from Cinder Cone blocked a creek in the 1600s?

Snag Lake. Its water seeps on beneath the lava to feed Butte Lake, itself the remnant of a bigger lake that the same flows partly filled.

Peter Lassen, namesake of the park, was shot dead in 1859 in a Nevada canyon while searching for what?

A silver mine. Gunmen fired on his camp at daybreak, killing Lassen and a companion; a third man escaped, and who pulled the triggers was never settled.

Which tree species dominates the forest belt between about 6,500 and 8,000 feet in the park?

Red fir, with deep-purple cones standing upright on its branches, forms nearly pure stands between about 6,500 and 8,000 feet; below that a mixed-conifer forest of ponderosa, Jeffrey and sugar pines and white fir takes over.

What turns patches of Lassen's lingering summer snow pink or red?

Cold-loving algae. They are really green algae carrying a red pigment that shields them from fierce mountain sunlight, and hikers call the result watermelon snow.