Mount Hood CRACKS OPEN - 200,000 Oregonians On DEATH ZONE Alert!

追加: 2026-05-05

[00:00:00]It is the probability over the next years that a river of volcanic concrete will sweep down the mountains flank and bury the eastern suburbs of Portland.

[00:00:07]Roll a single die. If it lands on one, the Lehar has come. And what makes Hood uniquely dangerous is not the lava. It is not even the eruption. It is the quicksand that Lewis and Clark already warned us about 220 years ago. They just did not know they were warning us. Let me explain.

[00:00:28]In 1997, the United States Geological Survey published Open File Report 9789.

[00:00:36]Seven authors, Scott, Pearson, Schilling, Costa, Gardner, Valance, Major.

[00:00:43]One sentence inside that report changed how geologists talk about Mount Hood forever. The probability of eruption generated laars affecting the sandy and white river valleys is 1 in5 to 1 in30 during the next 30 years. That is roughly a 6.7% annual probability at the high end. That is not a tail risk. That is not a 100red-year problem. That is about the odds of rolling a single die and getting a one every year for the next three decades.

[00:01:15]No other Cascade volcano has a near-term laahar probability this high. Not Reineer, not Baker, not Glacier Peak.

[00:01:23]Hood is the youngest. Hood is the most loaded. Hood is the one geologists speak about carefully. And there is a word they speak most carefully of all.

[00:01:32]Laahar. Alahar is not lava. Alahar is a river of concrete.

[00:01:40]wet volcanic ash, pulverized rock, melted glacier, and ripped up forest moving at freeway speed down a river valley. It does not glow. It does not warn. It sounds like a freight train.

[00:01:55]And it arrives like one. Mount Hood has produced them before. Mount Hood will produce them again.

[00:02:01]At 11,249 ft, Mount Hood wears 12 named glaciers and snow fields. Palmer, Reed, Zigzag, Sandy, White River, Elliot, Co. A crown of ice. Just below the summit at roughly 9,800 ft sits a feature called Crater Rock. Crater Rock is not a rock. It is a doit lava dome, a plug of extruded magma that forced its way to the surface sometime between 1781 and 1793.

[00:02:37]Today, the fummeral at its surface measures 89 degrees C near boiling. The gas coming out of its cracks analyzed by geothermometer registers above 300° C.

[00:02:49]That is a magmatic signature. That means there is still hot rock down there breathing.

[00:02:56]The surrounding summit is stret alteration. It means the hydrothermal system has been chemically eating the rock for two centuries. Altered rock is roughly 10 times weaker than fresh desight.

[00:03:12]Now put it together. Magma pushes up, pressurizes, and a new dome grows on or beside crater rock. The weakened acid cooked rock gives way. Pyrolastic flows race down the flanks at hurricane speed.

[00:03:27]Those flows cross 12 glaciers in seconds and flashmelt the ice. Within 10 minutes, a wall of volcanic concrete is moving down the zigzag river. Within 30 minutes, it has overwhelmed government camp and rodendren. Within 90 minutes, the laahar reaches Troutdale on the Colombia. This is not a worst case. This is the modeled case. And the geographic ladder below the mountain reads like a death warrant. Government camp zigzag Wildwood Brightwood Sandy Oregon population nearly 13,000.

[00:04:02]Gresham population 116,000.

[00:04:06]Troutdale population 16,500 built literally on the Sandy River Delta. That delta is not a river deposit. That delta is a lear deposit.

[00:04:21]Which brings us to Lewis and Clark.

[00:04:24]On November 3rd, 1805, William Clark walked to the mouth of an unnamed river flowing into the Colombia from the south. He tried to wait it. He wrote in his journal that he was astonished to find. The bottom was quick sand and impassible.

[00:04:40]He described a wide braided shallow channel, an island of coarse sand three miles long, and the water running brown and fast. They named it the Quicksand River.

[00:04:52]Modern Oregonians shortened the name.

[00:04:54]Today we call it the Sandy.

[00:04:57]Five months later, on April 1st, 1806, Sergeant Nathaniel Prior went upstream to scout it. He reported the bed was formed entirely of quicksand and that a pole could be driven 6 to 8 ft into the riverbed with no solid bottom. Here is what Lewis and Clark did not know.

[00:05:17]The old maid eruption of Mount Hood had ended roughly 10 to 20 years before they arrived. Tree ring dating puts it between 1781 and 1793. The expedition was standing in the freshest Lahar deposit in North American history. The quicks sand was not sand. It was fluidized volcanic ash and pulverized dayight still flushing down the valley two decades after the eruption that made it. When Lewis and Clark named the Sandy River Quicksand, they were not describing a river. They were describing a crime scene. And the killer is still on the mountain, which is why what happened on June 5th, 2021 got the attention of every volcanologist in the Pacific Northwest.

[00:06:00]That morning, a magnitude 3.9 earthquake struck 2 and a half miles south of Mount Hood's summit at a depth of 2.7 miles.

[00:06:08]It came with four shocks, and it came with an aftershock sequence. It followed a swarm of over 100 quakes in January 2021 and a 45minute swarm in March. Dr. Wes Thelen, geoysicist at the USGS Cascades Volcano Observatory, analyzed it. He said the swarm has all the characteristics of a tectonic swarm and that they were able to say with confidence that there was no inflation associated with this swarm. tectonic, not magmatic, no ground deformation.

[00:06:43]Good news. But catch what he also said.

[00:06:46]They could say that only because nine months earlier, USGS crews had installed three new monitoring stations on the mountain. Seismic GPS gas 9 months.

[00:07:02]That was the margin between knowing and guessing on Mount Hood.

[00:07:08]Dr. Allison Kolasar at Oregon State University explained to Oregon public broadcasting what the next eruption will probably look like. Most of the eruptions at Hood over the past 30,000 years have occurred in about the same way. Lava oozes up, forming a big lava dome. A blister of lava near the top of the volcano.

[00:07:31]A blister.

[00:07:33]a blister at 9,800 feet, sitting directly above 12 loaded glaciers, directly above the headarters of the Sandy and the Zigzag rivers, and directly above Timberline Lodge. This is where it gets personal. Timberline Lodge sits at 5,960 ft on the south flank of Mount Hood. It was built between 1936 and 1938 by Works Progress Administration craftsmen during the Great Depression.

[00:08:00]On September 28th, 1937, President Franklin Delano Roosevelt stood on its terrace and dedicated it.

[00:08:08]It is a national historic landmark.

[00:08:11]$350 a night for a room. The lobby window looks straight up at Crater Rock, less than 3 miles away, still fuming at 89° C. The USGS has mapped what is beneath the lodge's foundation. Much of the broad fan of pyrolastic flow and leare deposits underlies Timberline lodge and government camp. Tourists pay $350 a night to sleep on a tombstone.

[00:08:37]Beneath the W PA era timber floors, beneath the handcarved pioneer motifs, beneath the stone hearth laid in 1937, beneath the old growth beams is compacted volcanic debris from the last time this mountain did what it does. A guest sits by the fire, drinks a glass of organ pino, looks up through the lobby window at a steaming dayight dome less than three miles away, and has no idea the whole lodge is parked on the last eruption's receipt.

[00:09:07]Now, widen the lens. The Sandy River corridor exposure zone is not 5,000 people. That is the strict 500year hazard zone from Oregon's Department of Geology bulletin 0 1116.

[00:09:21]The true downstream totality, the full Sandy zigzag and lower Columbia corridor, counting Troutdale and eastern Gresham and the Interstate 84 interchange and the Bullr Run pipeline dependence approaches 200,000 Oregonians. Portland's primary drinking water comes from the Bull Run. 1 million people drink from it. The watershed itself is geographically protected by a ridge, but the pipelines that carry that water to Portland cross the Sandy River corridor. A laar that severs those pipelines cuts drinking water to all of them the same afternoon. Interstate 84 runs along the south bank of the Colombia. The Union Pacific mainline runs beside it. Alahar reaching the Colombia via the Sandy cuts both.

[00:10:05]Bonavville Dam sits 25 m downstream of the Sandy Columbia confluence catching the debris flood. Doggami has counted it up. 47,000 buildings inventoried across the study region. 104 schools and emergency response facilities, 1,600 m of road, 340 bridges, 944 electric transmission towers, 615 m of transmission lines. 20% of highway miles in Hood River County sit inside debris flow hazard zones. In 1980, a small debris flow on Palali Creek, not even an eruption, just rainfall on loose volcanic sediment, caused $13 million of damage and killed one person. That was a drizzle. Let the numbers land. 1 in 15 11,249 ft. 12 glaciers, 89 degrees C, 300 degrees C in the gas, 1 million bullrun drinkers, 47,000 buildings, 104 schools, 90 km of LAR reach, magnitude 3.9, 50 m to downtown Portland. So ask yourself three questions.

[00:11:19]How does a mountain with a 1 in5 probability of a valley filling LAR in the next 30 years still sit at alert level normal? How does a lodge dedicated by Franklin Roosevelt, built on pyrolastic flow debris, advertise itself as a honeymoon destination? And how does a river that Lewis and Clark literally could not walk across because it was still choked with the last eruption sand get a name softened to sandy and forgotten?

[00:11:48]Crater Rock is still steaming at 89° C tonight. 12 glaciers are still loaded above it. The Sandy River is still running brown through Troutdale every spring melt, carrying grain by grain, the last of the old maid eruption down to the Colombia. And Lewis and Clark's warning written in iron Gaul ink in 1805 is still true. The bottom is quicksand.

[00:12:14]The bottom is impassible. The bottom is still coming down the mountain.