Ice Age Floods

https://www.nps.gov/iafl/index.htm https://en.wikipedia.org/wiki/Ice_Age_Floods_National_Geologic_Trail The Ice Age Floods National Geologic Trail consists of a network of routes connecting facilities that will provide interpretation of the geological consequences of the Glacial Lake Missoula floods of the last glacial period that began about 110,000 years ago. It includes sites in Washington, Oregon, Idaho, and Montana. At the end of the last Ice Age, 18,000 to 15,000 years ago, an ice dam in northern Idaho created Glacial Lake Missoula stretching 3,000 square miles around Missoula, Montana. The dam burst and released flood waters across Washington, down the Columbia River into Oregon before reaching the Pacific Ocean. The Ice Age Floods forever changed the lives and landscape of the Pacific Northwest. To Trail Headquarters from Spokane Take I-90 West At Exit 277, merge onto US-2 toward Davenport/Fairchild AFB/Spokane Airport Just past Wilbur, turn right onto WA-21 Stay left onto Highway 174 Turn right onto WA-155 Stay on WA-155 past Grand Coulee Dam and into the town of Coulee Dam Cross the Columbia River and continue on WA-155 Turn right onto Crest Drive and follow up the hill. The HQ Office is located on the left Fort Spokane Visitor Center and Museum 4/30/2020 During COVID 19 Fort Spokane Visitor Center will remain closed until further notice. Fort Spokane Visitor Center and Museum are the former guardhouse, located in the middle of historic Fort Spokane. The visitor center and museum are open seasonally, from Memorial Day to Labor Day of each year. The visitor center and museum may be opened upon request the rest of the year. From Spokane, take I-90 West. At exit 277, merge onto US-2 toward Davenport/Fairchaild AFB/Spokane Airport. Turn right on WA-25. Follow WA-25 north approximately 23 miles. Look for signs for Fort Spokane Visitor Center and Museum. Green Monarch Ridge Green Monarch Ridge by Lake Pend Oreille ID Green Monarch Ridge by Lake Pend Oreille ID Steamboat Rock Large butte with lake in the foreground Steamboat Rock State Park, Washington Banks Lake Steamboat rock in the foreground with Banks Lake in the distance Banks Lake view from Steamboat Rock Dry Lakes Dry Lake lake bed and falls blanked with snow. Dry Lake lake bed and falls in winter Dry Falls A overhead shot of the Dry Falls area A beautiful shot from the ledge near the visitor's center in the Dry Falls area. Volcanic Necks and Plugs Volcanic necks are the remnants of a volcano’s conduit and plumbing system that remain after most of the rest of the volcano has been eroded away. photo of a riverside rocky spire with mountains in the distance

Ice Age Floods N a t i o n a l Geologic Trail M o n t a n a / Idaho / Washington / Oregon Ice Age Floods National Park Service U.S. Department of the Interior An erratic on Rattlesnake Mountain, Hanford Reach National Monument; Palouse Hills; Frenchman Coulee; Rhythmites at White Bluffs, Hanford Reach National Monument; West Bar Giant Current Ripples © BRUCE BJORNSTAD Floods of Change Imagine the greatest floods on earth crashing across and sculpting the lands of the northwestern United States. This incredible true story is recorded in rock and sediment. You can explore the geologic clues and landscapes made by the Ice Age Floods at sites along the Ice Age Floods National Geologic Trail. volume of Lake Ontario and Lake Erie combined—in just two days. A wall of water hundreds of feet high thundered downstream at 65 miles per hour (105 km/hour) with 10 times more water than all the world's rivers today. This massive flood of water, ice, and debris shook the ground as it raced westward over 16,000 square miles (41,440 km2) in presentday Montana, Idaho, Washington, and Oregon. Over thousands of years, an ice dam repeatedly formed and burst, causing dozens of floods. At the end of the last Ice Age, about 18,000 to 1 5,000 years ago, an ice dam blocked the Clark Fork River in what is now northern Idaho. Water rose 2,000 feet (610 m) behind the dam and stretched eastward 200 miles (322 km), creating Glacial Lake Missoula. Eventually, the ice dam weakened, burst, and released as much as 500 cubic miles (2,084 km3) of water—about the Today, widespread reminders of these Ice Age Fioous uot the landscape; gigantic basalt coulees, enormous dry falls, large boulders moved hundreds of miles, high water lines, and huge current ripples. These outstanding examples of cataclysmic flood geology, exceptional scenery, and places for scientific research are all part of the Ice Age Floods National Geologic Trail. J Harlen Bretz, 1882-1981 Solving the Mystery The story of the Ice Age Floods took nearly 50 years to piece together. During the 1920s-40s geologists debated the origin of eastern Washington's Channeled Scabland where eroded volcanic basalt surrounds braided channels and coulees. Most geologists believed that the Channeled Scabland was made by slow erosion by glaciers and streams. Geologic evidence that didn't fit with this idea led geologist J Harlen Bretz to hypothesize that the Channeled Scabland was formed by cataclysmic floods. Initially ridiculed, Bretz's hypothesis was validated when new technologies like satellite photography provided supporting evidence. By the 1970s it was universally accepted that the scoured landscape of the northwestern United States was the result of the Ice Age Floods. J Harlan Bretz C JULIAN GOLDSMITH A high school teacher turned geology professor, J Harlen Bretz was fascinated with the glacial geology of the Puget Sound. He became an expert on the features of stream and glacial erosion and began field research in the Channeled Scabland of eastern Washington in 1922. Challenging common beliefs, Bretz believed that the Channeled Scabland was formed not by ordinary stream erosion but by cataclysmic floods. What eluded him, though, was the source of the floods. Joseph Pardee, 1871-1960 Joseph Pardee USGS Joseph Pardee, a geologist with the US Geological Survey, proposed a source for Bretz's catastrophic floods. As he studied the Channeled Scabland and the intermountain basins of Montana in 1910, he found high water marks near Missoula, Montana—evidence of a large glacial lake. Later, in the Camas Prairie of northwestern Montana, he discovered giant ripple marks of sediment made by powerful currents flowing over the bottom of ancient Glacial Lake Missoula. Like Bretz, Pardee's discoveries played a key role in understanding the story of the Ice Age Floods. The work of these and present-day scientists show us that the gradual processes shaping our Earth can be punctuated by sudden, cataclysmic events, and that such events are possible in our lifetimes! The magnitude of the erosive changes wrought by these glacial streams is nothing short of amazing. —J Harlen Bretz, 1923 Lasting Impressions As the Ice Age Floods swept across the landscape from Montana to the Pacific Ocean, they eroded massive amounts of rock and debris from the land and deposited them farther down the flood route. Along the national geologic trail, deeply eroded coulees, scoured water gaps, remnant waterfalls, and basalt cliffs lead to gravel bars, giant ripple marks, and large boulders. These clues from the past guide your passage through geologic space and time. As you learn about 13 flood features here, find them on the map side of this brochure marked by numbered stars. 7. Dry Falls at Grand Coulee Fifty miles (80 km) northwest of Sunset Prairie Antidune Field, the mighty Columbia River flows. At the end of the Ice Ages, a lobe of the continental ice sheet diverted the Columbia River south along the path of

i l l e r a I e c Ginkgo Petrified Forest 7 Ripple marks 9 Lo be et g u P Lewis and Clark Interpretive Center ol C R be S ! ! ! O c e a n Beacon Rock State Park ! Columbia Hills Historical State Park Maryhill State Park ia b um l Co er Riv ! a k e Map Symbols Ice Age Floods National Geologic Trail, secondary route Area affected by ice-age floods Select ice-age floods site with associated geoheritage values recreation ecology science & research Wal l a Wal l a M O N TA N A geologic features economy culture The Floods Po rtlan d During the last ice age, between 12 and 17,000 years ago, glaciers covered much of northern Washington, Idaho, and Montana. The ice was miles thick in places. Portions of the glaciers repeatedly blocked large river drainages, forming ice dams. Lakes formed behind the ice dams, growing to small inland seas rivaling the size of the Great Lakes. The largest of these glacial lakes was Glacial Lake Missoula in what is now Montana. The lake was approximately 2,500 feet deep in places and extended over 3,000 square miles. It held as much water as about half of Lake Michigan. When the ice dam burst, all of the water suddenly drained in a matter of days, surging over Idaho, eastern Washington, and Oregon. The vast amount of water moving over a very short period of time carved the deeply scoured terrain that forms much of the dramatic landscape we see today. O R E G O N In the aftermath of the initial flood, the process of river blockage, ice-dam lake formation, and catastrophic release occurred repeatedly. Evidence suggests that there could have been as many as 100 separate floods at intervals of about every 50 years. The features it created are colossal. The water plucked giant columns out of the basalt, created smoothed mesas and giant potholes, and formed ripple marks between 15 and 30 feet tall. Collectively, this landscape is called the Channeled Scablands. The floods left behind many other distinctive features, such as, buttes, coulees, and flood bars. Palouse River Canyon 1 Eugene Ecology The ice-age floods left behind prime landscapes for recreation. State Parks, wildlife refuges, and other protected land ensures continued availability for public use and wildlife habitat. Visitors can take in the stunning views while hiking, camping, hunting, fishing, rock climbing, boating, bird watching, or wildlife viewing. The shrub steppe ecology found in eastern Washington supports many types of species only found in this type of environment. Flood-scoured basalt formations provide unique habitat for wildlife. The Hanford Reach region on the Columbia River provides habitat for a number of different species including migratory birds, native mammals, and spawning salmon. Current research on these landscapes is now being conducted by NASA. The channeled scablands closely resemble the surface of Mars, and offer a much closer locality for hands-on study. By studying the catastrophic effects of the water on the basalt landscape of Earth, scientists can correlate these to similar features on Mars. Places to go: Potholes State Park Places to go: Turnbull National Wildlife Refuge Places to go: The REACH-Hanford Reach Interpretive Center Bridgeport State Park Culture Economy The unique landscape left by the floods has been used by Native Americans for centuries. Historic campsites, petroglyphs, stone and bone tools, and other relics found along the paths of the floods, help us to better understand these ancestral peoples whose descendants still populate the region. The economy of the channeled scablands and the Pacific Northwest is supported by features created by the floods. The voluminous Columbia River discharges an average of 264,900 cubic feet per second. Industry in the dryland regions of eastern Washington depends on this lifeline for transportation, energy, agriculture, earth materials, and irrigation. The terrain left by the floods also influences how present-day Washingtonians use this region. Cultural exhibits at many of the selected sites have more information on the lives and livelihoods of those who call this territory their home. Places to go: Grand Coulee Dam Maryhill State Park Places to go: Columbia Hills Historical State Park Lewis & Clark Interpretive Center Fort Spokane Visitor Center Ginkgo Petrified Forest State Park Yakima Sportsman State Park Palouse Falls State Park Vineyards in eastern Washington 23 Native Americans fishing at Celilo Falls (now inundated by Lake Celilo) 21 Petroglyphs at Ginkgo Petrified Forest State Park 20 Data Sources: Ice Age Floods National Geologic Trail routes adapted from Ice Age Floods National Geologic Trail Long-Range Interpretive Plan Master Trail Map. Glacial ice and ice-age flood affected areas modified from Silkwood, J.T. (1998), Glacial Lake Missoula and the channeled scabland : a digital portrait of landforms of the last ice age, Washington, Oregon, northern Idaho, and western Montana,











Stev H. Ominski ©2002 Ice Age Floods at Dry Falls Lower Grand Coulee Bruce Bjornstad AA GUIDE GUIDE TO TO THE THE INCREDIBLE INCREDIBLE ICE ICE AGE AGE FLOODS FLOODS IN IN THE THE GRAND GRAND COULEE COULEE AREA AREA Northrup Lake Soap Lake/Ephrata, Washington FOLLOWING THE PATHWAY Our Lower Grand Coulee chapter of the Ice Age Floods Institute focuses on the beautiful Coulee Corridor National Scenic Byway. We serve Grant County and beyond, where we have 300 days of sunshine,140 lakes and only around eight inches of rainfall per year. During the last glacial cycle of the ice-age some 80,000 to 14,000 years ago, continental glaciers and repeated massive floods carved many of the unique distinguishing features of the Northwest’s interior landscape. We investigate the geological mystery of the Missoula Floods as it applies to this area, particularly Dry Falls, the centerpiece of this Disneyland for geologists. We are seeking answers to a geological mystery of what happened and how it happened thousands of years ago. We do this to unravel the mystery that was initially unlocked only 100 years ago from the breathtaking geological hints that were left behind. Nobody really knows what happened, but we are still making new discoveries each year and investigating the mystery to this day. We are local people meeting monthly in Soap Lake, WA, to plan hikes, gather geological samples, assist at Dry Falls Visitor Center, participate in local festivals, and distribute information such as in your hand now. You are invited to come help solve the mystery, and while here you can enjoy our playground, including: the Ephrata Fan, the Great Blade, Steamboat Rock, Ancient Lakes, Drumheller Channels, Sun Lakes, Lenore Caves, the Potholes Area, Soap Lake, and more. To learn more, to attend a presentation, or to help with our mystery, please visit us at https://IAFI.org/lower-grand-coulee/. Our Cataclysmic Floodscape This is your local guide to dramatic evidence of those cataclysmic forces, from spectacular canyons and cliffs to waterfalls and vast, flood-eroded scablands, that can be witnessed with a short road trip. It is our hope that you will use this guide to explore these fascinating geological features in our region and will want to learn more about the dramatic ice-age story of glaciers and floods. OF THE GREAT FLOODS Key resources for understanding the geology of the Mid-Columbia region: On the Trail of the Ice Age Floods Bjornstad, B. N., Vols. 1 & 2 DETAILED MAP INSIDE Highlighting Day Trips to prominent ice-age flood features in the Grand Coulee area A regional guide to geological evidence of the GREAT ICE AGE FLOODS that sculpted the Grand Coulee landscape Keokee Co. Publishing, Inc., Sandpoint, ID Learn MORE at IAFI.org or facebook.com/IceAgeFloods/ Dry Falls at Sunrise - Photo by David McWalter