I-5   Kalama, Washington  N 46° 00.232 W 122° 50.811 
The Kalama Narrows was the last choke point in the Bretz floods and produced the largest lake. As the flood waters exited the gorge it was 500 feet high. When the flood waters came to Kalama Narrows it backed up as far as Eugene, Oregon to the south and the Vancouver Plains 35 miles to the north.

00 - Kalama Narrows

Kalama Narrows

Vancouver, WA   N 45° 35.393 W 122° 28.456
The Missoula Ice Age Floods covered the city of Portland, Oregon in approximately 400 feet of water, depositing large volumes of unconsolidated silt, sand, gravel, boulders, trees and ice rafts with erratics. These floods also inundated the Vancouver plains north of the river encompassing about 275 square miles. As the west-flowing waters rushed around the basalt Camas bluff, sediments slowed and were deposited on the west side forming a sand and gravel bar that became Mill Plain Heights.

00A - Missoula Ice Age Floods - Mill Plain Gravel Bar

Missoula Ice Age Floods - Mill Plain Gravel Bar

This is a one and half to two hour driving tour of Missoula Ice Age Floods evidence in Clark and Skamania Counties. Highlights include: Mill Plain Gravel Bar, spectacular Cape Horn in the Columbia River Gorge, view of Beacon Rock on a clear day, Canyon Creek Channel, enormous basalt boulders in front yard, Washougal River Channel, Lacamas Park for a picnic and hike perhaps, Round and Lacamas (kolk) Lakes, and Prune Hill Overlook.

00B - Missoula Floods - Clark & Skamania Counties, WA

Missoula Floods - Clark & Skamania Counties, WA

Portland, OR  N 45° 34.492 W 122° 42.478 
The Willamette Bluffs at University of Portland was created by the outflow of the floodwaters.  The Overlook is where you can see the curved bare rock and dirt bluffs as well as Swan Island, the West Hills and downtown Portland in the distance to the south.  The floodwaters would have been more than 200 feet above your head.   The draining waters coming all the way from Eugene were flowing almost straight hitting the bluffs directly in a swirling eddy.  If the floodwaters had continued, the bluffs would have been cut through and a new river channel would have been created.

01 - Missoula Ice Age Floods at Willamette Bluffs

Missoula Ice Age Floods at Willamette Bluffs

Alameda Ridge was formed between 15,000 and 13,000 years ago at the end of the last ice age when the ice dam containing the 2000-foot deep, 200-mile-long Glacial Lake Missoula collapsed some 40 - 100 times, causing the Missoula Floods, some of the largest floods known on earth. The flood waters spilled across Idaho and eastern Washington, surged down the Columbia River and through the Gorge, flooding the Willamette Valley as far south as Eugene, Oregon. These floods covered the city of Portland in approximately 400 feet of water, carving out Sullivan's Gulch and the large ravine that holds Interstate 84, and depositing a large volumes of unconsolidated silt, sand, gravel, boulders, trees and ice rafts with erratics. As the west-flowing waters rushed around Rocky Butte, a volcanic cinder cone in the Boring Lava Field, sediments slowed and were deposited on the west side of the butte forming a gravel bar that became Alameda Ridge. The ridge extends west roughly 6 miles from Rocky Butte.

01A - Missoula Ice Age Floods - Alameda Ridge

Missoula Ice Age Floods - Alameda Ridge

Once past the Columbia River Gorge, the floodwaters slowed and spread as they poured out across the Portland area. The floodwaters temporarily formed a lake in the Willamette Valley to 350-400 feet above sea level, laying down large amounts of silt and gravel, creating the Alameda Ridge, as well as carving out Sullivan's Gulch Channel as the floodwaters sped west.  The gulch extends east from the Willamette River and originally was a forested riparian area featuring a spring-fed pool and waterfalls, which has since been filled.  Presently the gulch is a major urban transportation corridor, used by the MAX Light Rail system, several freight railways, as well as Interstate 84, the Banfield Expressway. 

Heading east on I-84, the Missoula Ice Age Floods scoured out the V-shaped gorge into a U-shaped gorge with spectacular waterfalls and unstable cliffs.

02 - Rocky Butte, Sullivan's Gulch and Ice Age Floods

Ice Age Floods, Rocky Butte and Sullivan's Gulch

Troutdale pendant bar, Mill Plain gravel bar, and Alameda Ridge were formed between 15,000 and 13,000 years ago at the end of the last ice age when the ice dam containing the 2000-foot deep, 200-mile-long Glacial Lake Missoula collapsed repeatedly some 40 - 100 times over 3,000 years, causing the Missoula Floods, some of the largest floods known on earth.

02A - Missoula Ice Age Floods - Troutdale Pendant

Missoula Ice Age Floods - Troutdale Pendant

Travel on the Old Columbia River Highway from Troutdale to Cascade Locks.  N 45° 32.008 W 122° 15.710 

The Chanticleer Point was another place impacted by the Missoula Ice Age Floods. These glacial lake outburst floods were the result of periodic sudden ruptures of the ice dam on the Clark Fork River that created Glacial Lake Missoula. After each ice dam rupture, the waters of the lake would rush across eastern Washington, down the Columbia River and into the Willamette Valley in western Oregon.  There was as many as 40 to 100 floods about 40 to 50 years apart.

03 - Chanticleer Point Crafted by Cataclysms

Chanticleer Point Crafted by Cataclysms

off I-84  Mosier, Oregon  N 45° 40.804 W 121° 24.532 

Erratic rocks from Canada, Montana and Idaho were carried by the Missoula Ice Age flood waters on or in chunks of glacial ice.  A large, white glacial erratic is located in a field of black rocks in this ODOT gravel pit.   This large white, angular boulder is about 6'x8'x12' and probably weighs between 30 to 40 tons.  Other smaller white, glacial erratic rocks occur on the mesa above the cliffs on private property.

04 - Missoula Ice Age Floods at Mosier Syncline flanks

Missoula Ice Age Floods at Mosier Syncline flanks

A fun cache in Mosier!  N 45° 41.006 W 121° 23.905 
"Well... you are not required to go inside [where you can purchase delicious ice cream], you can look through the window for this one. There is a cache located at this location. As you are Looking around at the Porsches, Just ask for the cache and it will be produced for you. This is mainly here for those that wish to find a cache and sign the logbook."  

05 - Porsche

Porsche

I-84   The Dalles, Oregon 97058

Waymark: Kolk Pond at Columbia River Discovery Center, The Dalles, Oregon

At the site of The Dalles Dam there is an extensive area of well-scoured scablands on the north bank of the river, as well as in the rivers channels. There is another area of scablands to the west of the river after it makes its northward turn. The hillsides between Maryhill and The Dalles show prominent strand lines, and large boulder erratics are located at 800 feet elevation in the vicinity of Maryhill.  An erratic has been moved to Maryhill and is located on the east side of the museum.

06 - Killer waves, Dude!

Killer waves, Dude!

N 45° 55.195 W 119° 18.284
Great view!

Read about the history of the Columbia River and the Lewis and Clark expedition. there is a picnic area and a great view of the dam.

06A - Umatilla Rapids

Umatilla Rapids

Hwy 730 (Twin Sisters/Two Sisters/The Sentinal)  N 46° 02.625 W 118° 56.400 
Wallula Gap Overlook Cache GCKVFE is across the Columbia River.

During the ice age floods, almost twice as much water entered the Wallula Gap, a natural water gap of the Columbia River, than could pass through. The body of water that backed up is named Lake Lewis, a temporary lake that only lasted a week or less; the amount of time it took for all the water to drain through the gap. 

07 - Fire, Ice and Flood

Fire, Ice and Flood

A cache by Bruce Bjornstad   N 46° 01.981 W 118° 57.739 
From Twin Sisters take Hwy 12 north to Pasco; cross to Kennewick; from Kennewick take SR 397 through Finley. Turn south onto Piert Rd and then left at Meales Rd. Continue 4.5 miles before turning onto Ayers Rd. Follow Ayers Rd to the end and park above railroad and the Columbia River.  Then hike.

08 - Wallula Gap Overlook

Wallula Gap Overlook

west of Tri Cities, Washington  Hwy 82
N 46° 12.241 W 119° 15.675 

The Missoula Ice Age Floods re-routed the Yakima River to its present-day course. As the rapidly moving flood waters bottle-necked at Wallula Gap the flood waters slowed down and pooled, dropping their loads of gravel, sand and silt in the Amon Basin. The youngest Missoula flood sediment, which is about 10,000 years old, covers most of the Amon Basin.  As a result of these gravel deposits blocking the path of the Yakima River, it cut a course right between Rattlesnake Mountain and Red Mountain, bringing the end to the old Yakima River channel, and the birth of the present Yakima River channel.

09 - Amon Basin Earthcache

Amon Basin Earthcache

SW of Richland, Washington  N 46° 14.173 W 119° 18.842 


As the ice dams broke, floodwaters reached the Pasco Basin where Badger Mountain is located. These floodwaters reached elevations surpassing 1200' above sea level and created what was known as Lake Lewis.  The lake was only temporary, however, gradually draining out of Wallula Gap.  The only other land one would have seen from this location when floodwaters forming Lake Lewis reached their maximum elevations, would only be the tops of Candy Mountain, Red Mountain and Rattlesnake Mountain located to the west. The mountain tops are often referred to as the Lake Lewis Isles.

10 - Lake Lewis Isles - Ice Age Floods Earthcache

Lake Lewis Isles - Ice Age Floods Earthcache

A cache by Bruce Bjornstad   N 46° 21.874 W 119° 28.510 

General Directions: From SR 225 turn off into parking lot for Rattlesnake Slope Wildlife Area between MP7 and MP8, six miles north of Benton City.  Hike the trails.

Erratics were brought here by the great Missoula Ice-Age floods. An erratic is the name given to rocks that are foreign and do not belong in an area. In the Pasco Basin are thousands of light-colored granitic boulders, unlike the only natural rock in this region, which is dark-colored basalt.  On the north slope of Rattlesnake Mountain, erratics and erratic clusters have been discovered up to an elevation of almost 1200 feet. 

11 - Rattlesnake Slope Erratics and Bergmounds

Rattlesnake Slope Erratics and Bergmounds

NE of Kenniwick/Pasco, Washington  
N 46° 21.138 W 118° 54.707 
Drive something like a four-wheel-drive vehicle with high clearance and take plenty of water.

When Lake Missoula  ice dam broke and the flood waters came rushing down eastern and central Washington, the flood waters could not all escape through the Wallula Gap and for less than a week Lake Lewis was formed. This flood carried debris from ice bergs, boulders, rocks, pebbles, sand, dirt, along with other organic items. As Lake Lewis pooled the current was less which allowed the some material to settle to the bottom of the lake. Not all of Lake Lewis made it to the Pacific Ocean. In bowl shape areas, pools and small lakes were formed and would eventually evaporate away until the beds were showing. A huge amount of sand was deposited and uncovered and was bare to the wind. The wind blows, dunes are formed. Juniper Dunes is one of those areas.

12 - JUNIPER DUNES

JUNIPER DUNES

12A - Tweety Bird

Tweety Bird

A cache by Bruce Bjornstad 
East of Kenniwick  N 46° 23.783 W 118° 40.019 
General Directions: From the Pasco-Kahlotus Hwy. turn right (south) onto Snake River Road. After 5 miles park where road ends at the Snake River.

Lake Sacajawea Bar is one of the largest depositional features left behind by the great Ice-Age floods. Geocache is located along the Columbia Plateau Trail, a rails to trails project under development, with an excellent view of the bar.

The bar is located 15 miles upstream of Ice Harbor Dam, which created Lake Sacajawea, a man-made reservoir along the Snake River. The bar rises abruptly to 400 feet above the river, making it one of the tallest Ice-Age flood bars.  The bar is being threatened by those who wish to mine it for the valuable gravel and sand they contain called aggregate. 

13 - Lake Sacajawea Flood Bar

Lake Sacajawea Flood Bar

Since at least the 1990’s people have been working toward the creation of an Ice Age Floods National Geological Trail.  The IAFI has worked from 1995 to the present to build support for this Trail.
  http://iafi.org/

The Ice Age Floods National Geologic Trail would essentially be a network of marked touring routes extending across parts of Montana, Idaho, Washington, and Oregon, with several special interpretive centers located across the region.

Sources:  Bruce Bjornstad's first book on the Ice Age Floods-"On the Trail of the Ice Age Flood  A geological field guide to the Mid-Columbia Basin" and his latest book: "On the Trail of the Ice Age Floods The Northern Reaches A geological field guide to northern Idaho and the Channeled Scabland".

YOU CAN START AT ANY POINT AND CONTINUE AROUND THE ICE AGE FLOODS TRAIL.  OR JUST DO SECTIONS OF THE IAF TRAIL.

IDAHO AND MONTANA IAF ARE LOCATED IN A SEPARATE BOOKMARK.