9:59:59.000,9:59:59.000 [Intro Music] 9:59:59.000,9:59:59.000 The Pacific Northwest is famous for many [br]things. 9:59:59.000,9:59:59.000 Including huge floods. 9:59:59.000,9:59:59.000 Floods of lava that buried almost 40%[br]of Washington, 9:59:59.000,9:59:59.000 and floods of Ice Age water that[br]created more than 2,000 square miles 9:59:59.000,9:59:59.000 of scab lands. 9:59:59.000,9:59:59.000 What are the odds that such rare events[br]both happened here in this corner of 9:59:59.000,9:59:59.000 North America? 9:59:59.000,9:59:59.000 We're just south of Lewiston Idaho at the[br]mouth of Hills Canyon, 9:59:59.000,9:59:59.000 the lowest point in the state. 9:59:59.000,9:59:59.000 The basalt bedrock here, 9:59:59.000,9:59:59.000 the floods of lava, came out of deep [br]cracks that formed in response to a heat 9:59:59.000,9:59:59.000 source that's now, in the state of[br]Wyoming. 9:59:59.000,9:59:59.000 A flood of water from a giant lake in Utah 9:59:59.000,9:59:59.000 came all the way through Southern Idaho,[br]through Hills Canyon, 9:59:59.000,9:59:59.000 dropped rocks here, and the water made it[br]to the Pacific Ocean. 9:59:59.000,9:59:59.000 A giant lake in Montana 9:59:59.000,9:59:59.000 flowed to the cascades, got backed up[br]to here. 9:59:59.000,9:59:59.000 Each of these layers representing a [br]separate flood. 9:59:59.000,9:59:59.000 The Columbia River basalts, 9:59:59.000,9:59:59.000 the Bonneville flood, 9:59:59.000,9:59:59.000 and the Missoula floods. 9:59:59.000,9:59:59.000 Let's dig into together and learn, 9:59:59.000,9:59:59.000 about huge floods in the Pacific [br]Northwest. 9:59:59.000,9:59:59.000 [ Music Plays ] 9:59:59.000,9:59:59.000 The Ice Age floods have helped exposed[br]and incredible pile of lavas 9:59:59.000,9:59:59.000 from erupting volcanoes that are not[br]related to our famous cascade volcanoes. 9:59:59.000,9:59:59.000 The Columbia River basalt group, 9:59:59.000,9:59:59.000 a pile of lava rock more then 2 miles[br]thick, 9:59:59.000,9:59:59.000 is an exception to the global rule. 9:59:59.000,9:59:59.000 Basalt lavas usually erupt in ocean [br]basins, 9:59:59.000,9:59:59.000 but these low silica lavas flooded North[br]America from below. 9:59:59.000,9:59:59.000 Much like a boat with a leak. 9:59:59.000,9:59:59.000 They're similar flood in central India,[br]southern Brazil, southern Africa, 9:59:59.000,9:59:59.000 and central Siberia. 9:59:59.000,9:59:59.000 In each case, very large volumes of fluid[br]basaltic magma 9:59:59.000,9:59:59.000 erupted rapidly from cracks and continents[br]to form sheets of lava rock covering 9:59:59.000,9:59:59.000 tens of thousands of square miles. 9:59:59.000,9:59:59.000 The deep crack called fissures cracked[br]the North American crust in south eastern 9:59:59.000,9:59:59.000 Washington and eastern Oregon,[br]starting 17.5 million years ago. 9:59:59.000,9:59:59.000 Today many geologist agree that the [br]fissures are directly related to the birth 9:59:59.000,9:59:59.000 of a tectonic hot spot, 9:59:59.000,9:59:59.000 beneath the out south-eastern Oregon[br]17.5 million years ago, 9:59:59.000,9:59:59.000 and now located underneath Yellowstone [br]National Park in Wyoming due to the 9:59:59.000,9:59:59.000 North American plates slowly moving over[br]the stationary hot spot. 9:59:59.000,9:59:59.000 These spectacular basalt lava eruptions, 9:59:59.000,9:59:59.000 more than 300 distinct events punctuated[br]by thousands of years of quiet between 9:59:59.000,9:59:59.000 each lava flood. 9:59:59.000,9:59:59.000 Flooded and buried, the rugged inland[br]landscape of the Pacific Northwest. 9:59:59.000,9:59:59.000 Many of the biggest lava flows made it[br]from their fissures in Idaho all the way 9:59:59.000,9:59:59.000 to the tower cliffs of the Oregon coast. 9:59:59.000,9:59:59.000 At Pasco Washington the stack of Columbia[br]River basalt lava flows is 1,600 ft. thick 9:59:59.000,9:59:59.000 more then 3 miles of lava. 9:59:59.000,9:59:59.000 Sitting on top of a 17 million year old[br]landscape. 9:59:59.000,9:59:59.000 There isn't one visage to see all the[br]lava flows, how could you? 9:59:59.000,9:59:59.000 To truly grasp the scale of the lava stack[br]one has to visit scattered canyons that 9:59:59.000,9:59:59.000 expose a dozen flows at a time, like[br]in the Yakama River Canyon, 9:59:59.000,9:59:59.000 and the Columbia River Gorge, 9:59:59.000,9:59:59.000 or in the Grand Coulee, 9:59:59.000,9:59:59.000 which was carved just thousands of years[br]ago, not millions. 9:59:59.000,9:59:59.000 By the Ice Age floods. 9:59:59.000,9:59:59.000 [ Music Plays ] 9:59:59.000,9:59:59.000 During the Ice Age, a thick ice sheet[br]covered much of North America, 9:59:59.000,9:59:59.000 advancing and retreating in response to[br]global climate. 9:59:59.000,9:59:59.000 In Washington, Canadian ice crossed the[br]border in different places. 9:59:59.000,9:59:59.000 West of the cascade range, the Puget Lobe[br]filled the Puget Lowland with 3,000 ft. 9:59:59.000,9:59:59.000 of ice, above present day Seattle. 9:59:59.000,9:59:59.000 With enormous erratics left behind 9:59:59.000,9:59:59.000 after the ice melted back. 9:59:59.000,9:59:59.000 Most Puget Sound residents live on[br]complicated sets of Ice Age deposits. 9:59:59.000,9:59:59.000 Glacial till, glacial outwash, that[br]reveal ice on the move. 9:59:59.000,9:59:59.000 Advancing and retreating with glacial[br]licks riding the front of an active 9:59:59.000,9:59:59.000 ice margin. 9:59:59.000,9:59:59.000 East of the cascades, the Okanogan Lobe[br]crept into north central Washington. 9:59:59.000,9:59:59.000 Gorgeous glacial moraines and impressive[br]glacial erratics 9:59:59.000,9:59:59.000 have been sitting on the Waterville[br]plateau for at least 12,000 years. 9:59:59.000,9:59:59.000 During some of the Okanagan ice advances,[br]the mighty Columbia River was diverted, 9:59:59.000,9:59:59.000 and sent due south, through the Grand[br]Coulee, 9:59:59.000,9:59:59.000 and over dry falls. 9:59:59.000,9:59:59.000 In northern Idaho, the Purcell Lobe [br]combined with the rugged topography 9:59:59.000,9:59:59.000 of the Bitterroot Mountains and blocked[br]Montana's Clark Fork River, 9:59:59.000,9:59:59.000 near present day Saint Point Idaho. 9:59:59.000,9:59:59.000 Glacial Lake Missoula formed as glacial[br]melt water backed up behind the ice 9:59:59.000,9:59:59.000 dam forming a huge lake, more then 3,000[br]square miles of western Montana. 9:59:59.000,9:59:59.000 Old shorelines of the lake are visible [br]above the University of Montana. 9:59:59.000,9:59:59.000 Faint water marks first noted in 1886[br]by T.C Chamberlin. 9:59:59.000,9:59:59.000 The lake was 950 ft. deep at Missoula and[br]twice that depth in neighboring valleys. 9:59:59.000,9:59:59.000 And then it happened, Glacial Lake[br]Missoula breeched the ice dam and raged 9:59:59.000,9:59:59.000 across eastern Washington. 9:59:59.000,9:59:59.000 Through the cascade range and reached the[br]mighty Pacific Ocean. 9:59:59.000,9:59:59.000 Up to 10 cubic miles per hour. 9:59:59.000,9:59:59.000 A rate 10 times the combined flows of all[br]the rivers on planet earth, 9:59:59.000,9:59:59.000 surged through Eddy Narrows, and other[br]narrow valleys in western Montana. 9:59:59.000,9:59:59.000 When the huge lake suddenly drained,[br]giant current ripples were created 9:59:59.000,9:59:59.000 on the lake's floor. 9:59:59.000,9:59:59.000 And the failed ice dam was replaced by a[br]new one, 9:59:59.000,9:59:59.000 and another Glacial Lake Missoula formed. 9:59:59.000,9:59:59.000 Which led to the next Missoula flood. 9:59:59.000,9:59:59.000 Drama repeated many times. 9:59:59.000,9:59:59.000 Banded deposits at the bottom of Glacial[br]Lake Missoula show the lake form dozens 9:59:59.000,9:59:59.000 of times and released quickly over [br]Washington each time. 9:59:59.000,9:59:59.000 Rinse and repeat up to 100 times. 9:59:59.000,9:59:59.000 These are slack water sediments from the[br]Missoula floods. 9:59:59.000,9:59:59.000 We're in Tammany Barge of south of [br]Lewiston Idaho. 9:59:59.000,9:59:59.000 Each of these is a separate Missoula [br]flood. 9:59:59.000,9:59:59.000 We're 150 miles upstream from Wallula gap [br]that means water from Montana 9:59:59.000,9:59:59.000 made it to Wallula gap and to back up this[br]far up the snake river drainage. 9:59:59.000,9:59:59.000 This is one event, still falling from[br]the bottom of Lake Lewis. 9:59:59.000,9:59:59.000 And another flood, and another flood. 9:59:59.000,9:59:59.000 Now that's amazing. 9:59:59.000,9:59:59.000 [ Music Plays ] 9:59:59.000,9:59:59.000 Meanwhile, another Ice Age flood, the [br]Bonneville flood, 9:59:59.000,9:59:59.000 happened around the time of Missoula[br]flooding. 9:59:59.000,9:59:59.000 Lake Bonneville, and Ice Age predecessor[br]to the Great Salt Lake. 9:59:59.000,9:59:59.000 Filled and spilled out of Utah and into[br]southern Idaho. 9:59:59.000,9:59:59.000 The old shorelines of Lake Bonneville, 9:59:59.000,9:59:59.000 ancient bathtub rings above Salt Lake[br]city were first described by G.K Gilbert 9:59:59.000,9:59:59.000 in 1890. 9:59:59.000,9:59:59.000 A desert under water. 9:59:59.000,9:59:59.000 Once the Bonneville basin was filled to[br]capacity, 17,400 years ago. 9:59:59.000,9:59:59.000 The erosion of loose rocky material at[br]Red Rock Pass led to the rapid 9:59:59.000,9:59:59.000 lowering of Bonneville, 9:59:59.000,9:59:59.000 and the Bonneville flood surged north[br]into Idaho snake river plane. 9:59:59.000,9:59:59.000 Unlike the Missoula floods and it's ice[br]dam, 9:59:59.000,9:59:59.000 the Bonneville flood involved a lot more[br]water then the biggest Missoula flood. 9:59:59.000,9:59:59.000 Probably about twice as much water. 9:59:59.000,9:59:59.000 But the constriction at Red Rock Pass that[br]had spilled out through 9:59:59.000,9:59:59.000 was much smaller then where the ice bridge[br]was breached in northern Idaho. 9:59:59.000,9:59:59.000 The Bonneville water came out slower. 9:59:59.000,9:59:59.000 So while the volume of Bonneville water[br]was twice as large as the largest Missoula 9:59:59.000,9:59:59.000 flood, the peak discharge was only[br]about 1/10 of the largest Missoula flood. 9:59:59.000,9:59:59.000 Each Missoula flood lasted for days. 9:59:59.000,9:59:59.000 The Bonneville flood lasted for weeks. 9:59:59.000,9:59:59.000 Gorgeous deposit. 9:59:59.000,9:59:59.000 All these rocks were deposited by the[br]Bonneville flood, 9:59:59.000,9:59:59.000 just one flood, right? 9:59:59.000,9:59:59.000 Just a few weeks all these rocks were[br]dropped. 9:59:59.000,9:59:59.000 17,400 years ago. 9:59:59.000,9:59:59.000 Sitting on top are Missoula flood[br]sediment, 9:59:59.000,9:59:59.000 there are 20 different Missoula food[br]layers here. 9:59:59.000,9:59:59.000 So at this spot, we had 20 Missoula floods[br]after the Bonneville flood. 9:59:59.000,9:59:59.000 So how do we know this stuff? 9:59:59.000,9:59:59.000 Carefully crafted geographic maps, 9:59:59.000,9:59:59.000 made in the field by generations of[br]geologists have measured both the 9:59:59.000,9:59:59.000 erosional chasms cut by the floods 9:59:59.000,9:59:59.000 and have catalogued piles of rocks and[br]layers of sediment that the floods have 9:59:59.000,9:59:59.000 left behind. 9:59:59.000,9:59:59.000 Water is scarce here in eastern [br]Washington today, it's a desert. 9:59:59.000,9:59:59.000 But the landscape has a strong stamp of [br]water, and lots of it. 9:59:59.000,9:59:59.000 The Ice Age floods tore up the crust,[br]revealing the Columbia River salt lavas 9:59:59.000,9:59:59.000 that flowed millions of years earlier. 9:59:59.000,9:59:59.000 Leaving dramatic landmarks like the Grand[br]Coulee, Dry Falls, the crisscrossing 9:59:59.000,9:59:59.000 flood paths of Drumheller Channels, 9:59:59.000,9:59:59.000 and Palouse Falls. 9:59:59.000,9:59:59.000 Tons of bedrock were hauled away by the[br]floods, 9:59:59.000,9:59:59.000 as the water exploited deep cracks in[br]the bedrock. 9:59:59.000,9:59:59.000 Box shaped valleys called Coulees formed, 9:59:59.000,9:59:59.000 where the most aggressive water did the[br]most digging. 9:59:59.000,9:59:59.000 Rock precut and hauled off by the flood[br]water cruising at more then 60 mph 9:59:59.000,9:59:59.000 in places. 9:59:59.000,9:59:59.000 And there are amazing potholes drilled by[br]the swirling dynamics of floodwater. 9:59:59.000,9:59:59.000 Often revealed in the vertical Coulee[br]walls, cut by the erosive ice age floods. 9:59:59.000,9:59:59.000 Lost worlds hidden in the salt bedrock. 9:59:59.000,9:59:59.000 At the bottom of key lava flows, pillow[br]structures were water battled lake water, 9:59:59.000,9:59:59.000 and petrified logs, provide detailed clues[br]to the ancient forests and lakes that 9:59:59.000,9:59:59.000 thrived in eastern Washington, during[br]the thousands of years between 9:59:59.000,9:59:59.000 devastating lava floods that repeatedly [br]buried vibrant thriving ecosystems 9:59:59.000,9:59:59.000 in thick lava. 9:59:59.000,9:59:59.000 A landscape full of life, with each lava[br]burial creating a lifeless, 9:59:59.000,9:59:59.000 featureless, moonscape. 9:59:59.000,9:59:59.000 Millions of years later, each of the 100[br]floods made it to the Pacific Ocean, 9:59:59.000,9:59:59.000 but does that mean that each flood[br]maintained 9:59:59.000,9:59:59.000 a high speed for Montana to the Coast? 9:59:59.000,9:59:59.000 No, like today there are many obstacles[br]to negotiate on a journey from the 9:59:59.000,9:59:59.000 Rocky's to the Pacific Ocean. 9:59:59.000,9:59:59.000 The Ice Age floods had the same [br]roadblocks. 9:59:59.000,9:59:59.000 Wallula Gap, eastern gateway to the[br]Columbia River gorge was a bottleneck 9:59:59.000,9:59:59.000 for the floods. 9:59:59.000,9:59:59.000 Every drop of Ice Age flood water needed[br]to squeeze through the gap, 9:59:59.000,9:59:59.000 which was the secret passage through[br]the cascades, 9:59:59.000,9:59:59.000 and onto the Pacific. 9:59:59.000,9:59:59.000 At Wallula Gap, flood water waiting to[br]enter became Lake Lewis. 9:59:59.000,9:59:59.000 The bigger the flood, the larger the[br]Lake Lewis. 9:59:59.000,9:59:59.000 Calm and dirt brown with suspended loose, 9:59:59.000,9:59:59.000 which crept up neighboring river valleys. 9:59:59.000,9:59:59.000 The Yakama river, the Walla Walla River, [br]and the Snake River. 9:59:59.000,9:59:59.000 The water of Lake Lewis must have gotten[br]clear with each passing day. 9:59:59.000,9:59:59.000 The fine grain material falling out of the[br]lake and onto the lake bottom, 9:59:59.000,9:59:59.000 the result? 9:59:59.000,9:59:59.000 Impressive layers of slack water sediment. 9:59:59.000,9:59:59.000 Each layer from each Lake Lewis. 9:59:59.000,9:59:59.000 And the surface of Lake Lewis was[br]full of icebergs. 9:59:59.000,9:59:59.000 How do we know that? 9:59:59.000,9:59:59.000 There are large erratics all across [br]central Washington that mark spots where 9:59:59.000,9:59:59.000 the icebergs drifted to the edge of the [br]lake. 9:59:59.000,9:59:59.000 Upstream some of the largest Missoula[br]floods came down of Columbia River 9:59:59.000,9:59:59.000 over Wenatchee. 9:59:59.000,9:59:59.000 And downstream Wenatchee, West bar is a [br]classic location to ponder the speed 9:59:59.000,9:59:59.000 and depth of the floods. 9:59:59.000,9:59:59.000 You old enough to remember the media [br]frenzy over Evil Kneviel daredevil jump 9:59:59.000,9:59:59.000 over the Snake River Canyon? 9:59:59.000,9:59:59.000 That's the canyon that the Bonneville[br]flood, 9:59:59.000,9:59:59.000 the one from Utah flowed through,[br]remember? 9:59:59.000,9:59:59.000 Lake Bonneville spilling over Red Rock[br]Pass and into the Snake River drainage 9:59:59.000,9:59:59.000 of Southern Idaho. 9:59:59.000,9:59:59.000 The floods scoured canyon walls[br]and gouged holes in the canyon floor. 9:59:59.000,9:59:59.000 Creating Shoshone Falls and Twin Falls. 9:59:59.000,9:59:59.000 The water ripping through the narrow[br]regions of the canyon, 9:59:59.000,9:59:59.000 dislodging the salt boulders, and[br]tumbling them down stream. 9:59:59.000,9:59:59.000 Where the flood channel widened, 9:59:59.000,9:59:59.000 the boulders were heaped into[br]impressive piles. 9:59:59.000,9:59:59.000 The Bonneville flood then entered Hells[br]Canyon, 9:59:59.000,9:59:59.000 the deepest canyon in North America, 9:59:59.000,9:59:59.000 before joining the channeled scab lands[br]of eastern Washington. 9:59:59.000,9:59:59.000 The deposits left by the flood give us[br]reach detail. 9:59:59.000,9:59:59.000 Giant flood bars, more then 100 ft. [br]above todays Snake River, 9:59:59.000,9:59:59.000 sit in narrow stretches of Hells Canyon,[br]showing us where the flood got choked up. 9:59:59.000,9:59:59.000 Creating flood stages hundreds of feet[br]feet high behind it. 9:59:59.000,9:59:59.000 In shlock water sediments are found all[br]through the Bonneville flood route, 9:59:59.000,9:59:59.000 but not the repetitive shlock water [br]sediments, like the Missoula Floods, 9:59:59.000,9:59:59.000 remember, there was just one Bonneville[br]flood. 9:59:59.000,9:59:59.000 All told, 100 different layers of shlock[br]water sediment have been documented 9:59:59.000,9:59:59.000 in eastern Washington. 9:59:59.000,9:59:59.000 100 Missoula floods! 9:59:59.000,9:59:59.000 But there is work yet to be done. 9:59:59.000,9:59:59.000 What's the age of each flood? 9:59:59.000,9:59:59.000 Is a more complete record of the Ice Age[br]flood sitting in the Pacific Ocean at the 9:59:59.000,9:59:59.000 mouth of the Columbia River? 9:59:59.000,9:59:59.000 And with the floods of lava, why did such[br]pure oceanic lava flood a 9:59:59.000,9:59:59.000 continental scene? 9:59:59.000,9:59:59.000 And how did the lava stay molten for 300[br]miles? 9:59:59.000,9:59:59.000 Much yet to be determined. 9:59:59.000,9:59:59.000 With our huge floods, in the Pacific[br]North West. 9:59:59.000,9:59:59.000 [ Outro Music Plays ]