the snow pack over your head splits in two right in front of your eyes and starts tumbling down in the Frozen slope to its resting place Far Far Below anything in its way is crushed under the immense mass of snow and debris you're witnessing an avalanche one of the most dangerous natural disasters but what if I tell you about another kind of avalanche no less blood chilling than the mountain one and the most bizarre thing about it is that it occurs underwater underwater Avalanches are powerful and disastrous natural phenomena often much more dangerous than land
ones they have the potential to wreak havoc on the entire planet leading to catastrophic consequences the most alarming thing they occur all the time under the surface of the ocean impossible to see predict and extremely difficult to measure such Avalanches can get 100 times larger than land ones and they pose a great risk to the world's Communications capable of leaving the entire planet without the internet but we'll talk about it a bit later first let's go 60,000 years back into the past we're near the northwest coast of Africa ready to witness the Colossal scale and
devastating impact of a ginormous underwater Avalanche it started as a quite small underwater landslide in the agader canyon at first it was just .35 cubic miles of material but in no time this Mass increased more than 100 times in size while traveling across the Atlantic ocean floor as the Avalanche sped up and grew it picked up gravel sand rocks and mud it carved a devastating path through one of the world's largest submarine canyons wiping out all forms of animal and plant life on its way the disastrous flow was so powerful that it literally eroded 250
M stretch of the canyon cutting hundreds of feet into its sides and damaging a total area of 1,740 sare miles that's the area of more than 3 and a half New York cities as for the force of the flow it was so immense that it propelled massive Boulders up the canyon walls to Heights of up to 430 ft before scientists discovered the evidence of this catastrophic event they had seriously underestimated the scale of Destruction caused by submarine Avalanches by the way these devastating catastrophes can start not only far away in the ocean but also at
estuaries let's go back to 14 January 20120 and see for ourselves a turbidity current a rapid downhill flow of water containing a lot of sediment rushed more than 680 M from the Congo River Estuary in the deep sea this current appeared due to two factors terrible flooding along the Congo River in late December 2019 and unusually large spring tides this resulted in an avalanche of sand and mud its volume was equivalent to 1/3 of all the sediment produced annually by all the rivers in the world this sediment Avalanche accelerated increasing in speed from 17 ft
per second in the upper part of the Congo Canyon to 26 ft per second when it reached the end of the Channel almost 700 M away from the coastline this route made it the longest Avalanche of sediment ever measured on our Planet 2 Days Later the flow reached the deep ocean the Avalanche broke two seabed telecommunication cables cutting internet data speeds all the way across West Central and South Africa now before this disaster scientists considered that measuring powerful deep sea Avalanches was impracticable but the sediment flow in the Congo Canyon could be monitored directly finally
allowing researchers to assess how major river floods connected to the deep sea they also concluded that how often underwater Avalanches occurred depended on where the Observer was seafloor Canyons that are close to River mouths can experience several tiny Avalanches per year other systems far from River discharges like the agadir canyon can only have one monster of an avalanche every 10,000 years or so you're likely wondering what can trigger an avalanche under the surface of the ocean well earthquakes typhoons High Tides river floods and even volcanic eruptions and due to our changing climate such events become
more and more frequent and intense at the same time these triggers don't mean that an avalanche is bound to happen nor do they relate to the scale of the event see for yourself in 1755 a powerful earthquake hit the coast of Portugal wiping out large parts of Lisbon tens of thousands of people lost their lives during that disaster but it only triggered a tiny underwater Avalanche and in 1929 a large earthquake off the coast of New Finland Canada triggered the largest underwater Avalanche ever recorded the flow traveled at a speed of 42 mph carrying Boulders
sand and mud it snapped 11 seabed cables on its Journey downhill the Avalanche was so powerful It produced a tsunami that claimed the lives of 28 people along the coastline now submarine Avalanches are totally invisible because they happen deep under the ocean surface which makes them extremely hard to study but we must find a way because these flows are super important they transport sediments nutrients and even pollutants across the ocean floor so a research team from Liverpool decided to unravel this mystery over the last 40 years they've collected more than 300 samples from the ocean
floor combined with seismic and bimetric data which is a fancy word for ocean mapping they managed to reconstruct a massive submarine Avalanche it was the first time an underwater Avalanche of this size was mapped out an even cooler thing the event itself started off pretty modestly but it quickly evolved into a colossal Avalanche that grew to more than 650 ft tall to put that into perspective imagine a skyscraper sized Avalanche zooming from Liverpool to London cutting a trench 100 ft deep and 9 M wide then it spread out over an area bigger than the UK
covering it with several feet of sand and mud that's like burying a whole country these findings are actually a big deal because they show that even a small underwater Landslide can turn into something massive and super destructive but that's not the worst think about undersea internet cables which are essential for Global Communication there are more than 550 active seafloor cables around the world their combined length is a whopping 870,000 Mi that's enough to wrap around our planet 35 times s when a submarine Avalanche breaks seafloor cables the effects are usually super expensive and devastating for
example in 2006 an earthquake in Taiwan triggered underwater Avalanches that cut loads of seafloor cables connecting southeast Asia with the rest of the world the largest internet operator in China had a 90% loss of traffic to the USA at the peak of the event as for Taiwan itself it experienced between 74 to 100% loss in traffic to neighboring Islands so now you probably get why we need to learn more about this natural phenomenon luckily researchers at Tain University have found a way to study it in 3D previous studies only looked at submarine avalanches in 2D
which didn't give the full picture of how they actually behaved the new research focused on how underwater flows interacted with mini basins natural features on the ocean floor that look like shallow bowls despite being called mini these bowls can be huge up to 4 square miles when turbidity currents flow into these mini basins they don't just stop no they hit the far side and curl back around like water Eddies in a stream these swirling flows move the sediment around before it settles on the ocean floor the size of the mini Basin and the speed of
the flow can change how the current behaves if the Basin is big and the current is slow it starts to fill up with sediment but if you crank up the flow speed or Shrink the Basin the current starts to overflow spilling over the Basin to study all this the researchers created a mini version of a mini Basin in a pool and used different speeds of flow to simulate turbidity currents they even made their own sediment mixers to see how different sizes of particles would behave in the end they managed to mimic real life ocean conditions
but on a smaller manageable scale pretty cool huh that's it for today so hey if you pacified your curiosity then give the video a like and share it with your friends or if you want more just click on these videos and stay on the bright side
