The Gorge rock formationsSeptember 13 in the United States
as you travel along the river you pass into a drier climate and the sun comes out!
you notice the change in vegetation from big conifers (doug firs, big leaf maples and hemlock) wet temperate rain forrest to the drier interior forests we see around Keremeous in BC. these forests are Ponderosa pine, bunchgrass forests (and some oregon white oak too quercus garryana according to wiki). This occurs around Hood River and The Dalles. Then you go into even drier territory with only the grassland and sage scrub......amazing such a transition in really such a short drive only around 100 miles. This is why it is so nice to vacation in Eastern Oregon. The temperature is always higher than Western Oregon and the sun tends to shine........However these days the down fall is there are way more fires and we saw lots and lots of evidence of brush fires that had burnt off the vegetation along the entire hillside on both sides of the river.
On our route home we camped at Deschutes River State Park, where we have camped quite a few times before. Lovely spot on the river, nice bike trail along an old railway bed behind the campground that goes into the deschutes river canyon......this year it was black from the campground back. Apparently there had been a fire here july 2 2018 and it burned both sides of the canyon back 20 miles...... This river is a popular fishing river, but the fishing guides think the fish are ok as the grassland at the edges of the river did not get burnt. There were lots of fishermen in the campsite when we were there, so I hope the fishing is still good.
You can see lots and lots of the Columnar Basaltic rocks all along the gorge. These are the columnar rocks created when thick magma cools. They are the same sort of rocks from the Giant Causway in Ireland. see here for a cool video of how basalt columns form: ( https://www.youtube.com/watch?v=cWGoiOFgpKI )
This fellow Nick has a huge series of videos about geology. Very interesting if you want to delve into the Gorge's geology. You have the base rock of Columnar basalts and many lava floods over the years. (17.5 MYA) -Columbia river basalt group - This is why so many layers -these basalts formed from lava from cracks (fissures) in the continental crust that are now over in Wyoming, (yellowstone). But on top of that you have 2 huge Glacial Lakes. One called Lake Bonneville, that covered Utah and Idaho and today the remnant of this lake is the Great Salt Lake in Utah. It gave way 17000 yrs BP, one time only. And a 2nd glacial lake called Glacial lake Missoula in Montana, that gave way in the Pliestocene (glacial times 12,000 bp) over 100 times.
Lake Bonneville reached capacity when the Bear river from Wyoming changed direction and started flowing into lake Bonnevile rather than going into the Snake river. eventually the rock damming the lake at Red rock pass eroded and the lake gave way. It happened one time and took about 6 weeks to empty. The amount of water was twice that of Glacial lake Missoula, but the flow rate was less. it was constricted at Red Rock pass. It carried many large Basalt boulders with it, which it had carved from the canyon walls, and you can see these in the rock layers along the corridors where they are exposed in the Bonneville layer. Sediment mixed with large boulders. You also seen them in the Snake river canyon in Idaho, in the farmers fields they call them "Melon Gravel". Huge boulders of basalt that were dropped as the waters energy lessened.... We will see these later in our road trip as we basically follow the path of the Snake river and then the flood through Red Rock pass to get to the Great Salt lake in Utah
For Glacial Lake Missoula, the ice dam broke, and a huge amount of water came flowing down the ancestral Columbia river.....it came down very quickly with a lot of force and a lot of water so carved out the channels deeper and deeper is my understanding. It also backed up at certain choke points - Wallula gap- and gave rise to other glacial lakes such as Lake Lewis in Eastern Washington. Lake Missoula emptied over 100 times in the pliestocene (glacial times) and took a day to empty.
Bonnevile broke only once and took 6 weeks to flow out (1700 BP) , Missoula broke many times (1200 BP ) and reformed but gushed out in days.
another cool u tube video regarding this from nick: (https://www.youtube.com/watch?v=i1BFb_uYlFQ )Read more