What happened to mountainsides during Helene's extreme rains (30 inches or more)?

Helene has impacted Appalachian life in extreme ways for the foreseeable future. In addition to catastrophic flooding, deadly landsliding occurred in numerous areas. The Garren Creek community of Buncombe County, North Carolina, may have been the area most severely affected by landslides. Huge debris flows claimed many lives in this area, and while the story has appeared on national news outlets, it has not received the attention that more populated areas have. This video talks about the disastrous debris flows in this area and how debris flows work in general. The video contains information for first responders about the risks of working in a debris flow area following the first pulse, as well as for mountain residents who may live in areas that could be hit by debris flows.

[Agent.]

That is my road. I live 1.38 miles east of the mudslide, as the crow flies, just off the right edge of your screen. Those were my neighbors, my church friends, my fire dept. It has been a deeply traumatic and devastating event for the community. That fireman who died, died alongside his nephew, who was also trying to rescue people. 11 members of one extended family were lost. The last body was recovered two days ago. SAR continues in other areas. People further south below that slide had bodies in their yards. My workman escaped with his mother and sister with their very lives. So much death that’s not reflected in the official numbers yet. And this is just one area. The sheer number of small towns and communities that had rockslides, mudslides, and flooding, is hard to wrap your mind around. Literally spanning hundreds of miles from eastern Tennessee and throughout western NC, with flooding all the way east in Charlotte. And from Florida’s big bend to Georgia, South Carolina, up to Virginia. No one understands how WIDESPREAD the devastation is and how unusual and severe, unless you’re there.

I appreciate this analysis very much. It helps me understand the dynamics of the geography where I am and has me evaluating my property in a new way.

[peterlecraw]

I've been driving in WNC delivering supplies and setting up starlinks.

Entire hillsides have had all their trees toppled, many trees are entirely stripped of their leaves and on one particular hillside I saw the trees stripped down to telephone poles. Every creek has mud and silt, every bridge has a pile of debris next to it. The churches feel like field hospitals in a war zone, power is spotty, cell service is nonexistant, and next week the temps are plummeting to close to freezing. Dozens of bridges are gone, it's a crapshoot if you're trying to actually move across rivers.

The situation on the ground in WNC is a literal hellscape. The depth and breadth of the damage sustained is virtually impossible to comprehend. Thank you for this video.

[silentrage]

I don't think people really comprehend the destruction to Western North Carolina. I live just south of Asheville, on the scale we got lucky here. The stream near my house went from maybe 2 or 3 feet across and just a few inches deep to a raging 30 feet wide and more than 15 feet deep. There was so much power behind that water that it pushed the culvert pipe out from under the road. The nearest big river to me is the French Broad River. It wasn't 10 feet over flood stage. It was 10 feet over the previous record flood. People are claiming that the "smell of death" isn't hanging in the air. I would invite them to sit on my porch and try to have a glass of tea or cup of coffee. I'm worried now because the stores are running out of food. I went to the store today to get a jar of mayonnaise. Not only were they out of mayo, they were out of fresh meat, no dairy, no cleaning supplies, no dog or cat food, no can goods, there weren't even any scented candles. I lived in Florida for nearly 30 years, and the only storm that came close to this would have been Charlie in 2004. Even with Charlie, they were able to clear the roads in a couple of days. Here, a lot of the roads are just gone.

[hopeblume]

Ty for explaining this. I’ve not seen anyone explain the mechanics of how this happened. Very informative and much appreciated.

[billmalvey]

I'm a geologist as well and I've been trying to explain to people how the topography in that region amplified the terrible affect of Helene and how that contrasts to Milton making landfall in crossing the essentially a flat landscape. Great video well done. And is that an RC plane I see in the background if so I'm another RC flying geologist

[SnowyOwlPrepper]

In 2019 I wrote a report about potential issues resulting from use changes in a 145 square mile area in Tennessee. It was a call to action I handed to our senator that a modern USGS investigation was needed. The last time one was done was about 1930. In the town at the mouth of the river, flooding was the major cause for loss in this town’s history. Rechanalization of the river in the town put historical important structures at risk. During this Helene event the river went back to the historical channel causing loss of property again. 6000 feet of relief between the headwaters and the mouth. The destruction of lives and property upstream was consistent with the widespread losses in this county bordering with North Carolina. Needless to say the study was not conducted. In my research for past floods I found descriptions of waterspouts forming on the surface of a river then dumping it on the slopes adjacent to the river where torrential rains were falling. The boulders in the past debris flows are a testament to the energy released in these large events. I wonder how many of these hydrologic basins are not being understood because of reasons that are just as dangerous.

[Becca-zdnh]

This is the first time I’ve seen one of your videos. It is so well done! I appreciate how you present the info on screen and the matter of fact way you talked me (someone with no knowledge of geology or geographical landscapes) through it. Thanks for the help in understanding what happened, and why some people were spared and others were not.

[aureaphilos]

We experienced similar debris flows in Vermont after Hurricane Irene hit in 2012. Our souls are on glacial till, which usually provides excellent drainage, but the 8-10 inches dumped statewide by Irene was extreme for our area. The worst damage I saw came from channels where fallen trees or blocked culverts created momentary dams across the channel; they allowed debris to build up and compound the power and scouring downstream. Good video!

[nottim]

Seriously your videos are a fantastic resource for understanding the Appalachian geology. Thank you for sharing your perspective and insight on these processes! Very very interesting.

[jkeelsnc]

I grew up in Black Mountain and my mother still lives in Swannanoa. Fortunately, she did not lose her house. Growing up no one ever talked about this level of flooding or debris flows. When I was an adult I learned about the 1916 floods but nothing about debris flows were mentioned even then. Not even our elderly neighbors from the area ever mentioned anything like this. I always had concerns about landslides on steep slopes and flooding along creeks and rivers which did happen occasionally but nothing that compares to this. I hope that the state and counties get involved in preventing any rebuilding or construction in the areas that have been wiped out indefinitely. It appears to me that the full extent of these events are often forgotten within 3 or 4 generations and then we are back to “business as usual”. A point needs to be made to keep the record of Helene active and refreshed in the minds of people in the region for generations. It must not be forgotten. The loss of life must be far worse than is commonly known given that people are describing the smell of death outside near these effected areas. I don’t live in WNC anymore. I suppose I’ll never go back now. The economy will be ruined for quite some time and many small and back roads that go into remote coves and valleys may be gone forever. A very sad tragedy that I could not have conceived of to this extreme prior to Helene.

[Ppittman]

Thanks for explaining this to people. It amazes me about all the lies or how could this happen. I'm glad to be alive without power 14 days later and not going to see any for a while. I had 17 inches of rain at my house in 2 days and the ground was soaked before Helene got here. The wind effect on the mountain ridgelines was catastrophic. The land between the creeks, rivers and ridgetops were hardly touched besides the landslides. I live in Mitchell County NC. I was able to get to Johnson City Tennesee on Saturday after the storm. After we crossed into Tennesee on Iron Mountain most of the damage was at the top of mountain. When we got to bottom in Unicoe TN, we couldn't even tell there was a storm. In Johnson City there was no hint of the devastation just 25 miles away. Everyone was having a normal day.

[brucemattes]

I was stationed at Huckleberry Creek Mountain Training Camp, an adjunct training base to Ft. Lewis, Washington, during the winter of 1977-1978. Huckleberry Creek Mountain Training Camp was located in the Snoqualmie National Forest less than a mile outside of the northeastern border of Mt. Ranier National Park.

Snow began falling at high elevations on Mt. Ranier as early as August in 1977. Simultaneously, it was raining in a typical Pacific Northwest fashion down at most of the lower elevations west of the mountain. No flooding, just your typical fall/winter swelling of every waterway flowing down off the slopes of Mt. Ranier towards Puget Sound.

By very early December, it had been snowing intermittently, but steadily, on Mt. Ranier for over 4 months, with significant accumulations of new snow far down into the timberlines of the mountain. Suddenly, the weather patterns took a turn for the worse, and within a period of just several days it began to steadily rain for weeks all the way up in elevation above Mt. Ranier's summit.

Within a week ALL of that early season snow on Mt. Ranier had melted, and the glaciers on Ranier began to melt as well. Every single tributary flowing off of Ranier became a raging torrent with boulders the size of a Volkswagen Beetle as well as entire first growth Douglas fir trees and Western Red Cedar trees having their root balls undermined, uprooted, falling over into the flood waters, and being washed downstream towards Puget Sound.

Huckleberry Creek, normally less than 8" deep and several feet wide, swelled to over 50 yards wide and between 10' and 20' deep. The tiny wooden bridge into camp off of Highway 410 that was capable of carrying the weight of a fully-loaded logging truck washed away on the first day of the catastrophic flooding, trapping us in the camp..Because of our skillsets as mountain training instructors, we were eventually able to construct a somewhat precarious but relatively stable rope assisted bridge across a humongous log/tree/debris jam that formed in a tiny bend of Huckleberry Creek just outside the elevated perimeter of our camp.

For approximately 10 days, until the flood waters subsided sufficiently to allow a bulldozer from Ft. Lewis to create a temporary road through the newly scoured bed of Huckleberry Creek where the bridge once stood, we horizontally belayed every person crossing that log jam in either direction, into or out of camp, from both sides of that jam. The only exception to that rule was the the first person to cross the jam in either direction, who was then responsible for setting up the belay station on the opposite side of the jam so that if someone slipped off of those slick tree trunks and lost their grip on the rope handlines that were located at waist height, then they would not suffer a serious injury.

That was my second experience with catastrophic flooding. The first was the aftermath of Hurricane Agnes in 1972 in central Maryland, where I was born and raised. The flooding in western Washington paled in comparison to what I saw in Maryland 5 years previously. Unless and until you experience something like what happened to me back in the 1970's or what has happened this year across the entire southeastern United States from Hurricane Helene, then you simply cannot wrap your head around the scale of destruction and death that Mother Nature is capable of handing out to we frail humans.

*My heartfelt prayers go out to everyone affected by Helene and Milton, especially those who lost family, friends, and neighbors.*

[sheilam]

This is what I have been looking for; a very comprehensive explanation with diagrams or pictures of the geophysics of the landscape showing what happened, the how and why of it all. The LIDAR Imaging was a bonus, a very helpful bonus. With all of the local vids of during and after I was watching the terrane and trying to visualize the mountains with and without the foliage, trees and grasses to imagine the speed and amount of water that swept across this area. Thx for doing this and sharing it.

[dlynnmorse]

Thank you for this explanation. I'm one of issu my road is 2 miles @ 4000 ft above Cox Creek. When I saw the start of torrent of water and mud I knew neighborhood below was going to have issues. Literally made my road part of the creek . Prayers to all.

[TheJttv]

Thank you for this. Stellar presentation, amazing drawing skills too

[rpehlman]

Wow, You answered all my questions!! So I heard that the area was saturated before Helene, but. You are also talking about the instability of what the landscape is made of compared to other elevated areas in the Appalachian mountains.Thankyou. I love the comparison of debris flows

[cumberlandquiltchic]

Excellent, excellent video’ I’ve watched it many times. I live here. You are the only person I’ve seen explaining this, in this way!
For me, I’ve been seeing more landslides (didn’t impact anyone directly) and even with just normal rainfalls for this area… it’s very troubling. Thank you for this. Great explanation!!!

[Astronetics]

This was possibly THE BEST explanation of the dynamics involved in all the destruction. For someone who is not an expert, your presentation was incredibly informative.

Commenting to bump up so more people see this video.

[elf]

Thank you for analyzing how this tragedy happened. I have family in Black Mountain. Luckily, their home was spared, but there is still no water or Internet. The massive amount of devastation is overwhelming. I donated to the Cajun Navy to help the mule trains in the mountains. The major highways may only be completely restored, and it will take a decade? Now, I understand why. People lived in the lower area because that was the only flat area available, and it had been over one hundred years since the last hurricane or flooding of such magnitude. The scope of this tragedy is just..there are no words.

[patsy]

Thanks so much for this video. I’ve puzzled about how such catastrophic scenes as happened in Western NC could occur. You are the first You Tuber who has explained the sequence in detail. Subscribed.