I was talking to my geology professor buddy the other day and he told me that there is emerging evidence that Bend, many years ago, suffered a Biblical-level flood. But that shouldn’t be too surprising.
More on that flood in a little bit. We’ll actually start this story with one of the biggest floods ever to be unleashed on planet Earth. It started just up the road in Montana during the last ice age.
“For my money, this is like the biggest geology story in our region,” said Hal Wershow, Assistant Professor of Geology at Central Oregon Community College. “Historically, it really put the Pacific Northwest on the map because it was such a big deal geologically. Nobody at the time in the early 1900s thought it was possible to have huge epic floods that defy the imagination.”
While there have been many catastrophic ice dam floods throughout Earth’s history, around 15,000 years ago (give or take a few thousand) an ice dam was created near modern-day Missoula, Montana, that backed up for so long that the water reached over 2,000 feet deep and the volume was that of Lake Ontario and Lake Eerie combined.
Until one day, the ice just couldn’t take it anymore. And years of accumulating water, building higher and higher and pushing harder and harder on that ice, completely drained out in about two days.
“So, the lake comes ripping out and it rips its way through western Montana and all through eastern Washington and in eastern Washington did tremendous damage. The scale of erosion is almost incomprehensible,” Wershow said.
We do know that humans were in the area when it happened and if they were on safe ground. It would have been a spectacular site as it slammed through Washington and eventually gravity carried it down to the Columbia River gorge.
“The Missoula floods did not create the Columbia Gorge. It was already there. They just made it bigger,” Wershow siad.
The volume and speed of the water was so extreme that tributaries like the Deschutes River actually reversed course and evidence of the sediment traveled for miles upstream.
“The water would have flowed upstream, which is kind of crazy to think about water flowing upstream and was dumping sediment all the way up to Maupin,” Wershow said.
The flood eventually made it down to the Willamette Valley and deposited all that wonderful sediment it was carrying, turning the area into the bountiful center of agriculture that it is today.
So — back to that Bend flood we were telling you about.
“So, we’ve started looking for more and more of these big floods. And the more we look, the more we find. And what we know is that there’s a tremendous pile of lake sediments all over Sunriver and La Pine. Hundreds of feet of lake sediments,” Wershow said.
And if you’d been in Bend when the lake dam broke, you probably would have wanted to gather your animals two by two.
“And now we’re just starting to find evidence that there was a big epic flood, meaning the dam would have catastrophically broken all at once and huge amounts of water would have gone rip down the Deschutes, through Bend and beyond,” Wershow said.
And you don’t have to go far to see the evidence of this epic flood. Wershow says the best evidence is at Riley Ranch.
“If you go hiking at Riley Ranch, you’re hiking up on the plateau and then you drop down Ryan’s Run. And then right in front of you, there’s almost an island. It’s a hill, so it’s not an island. But it’s surrounded by channels on either side. That hill has boulders on the top of it. We’re talking at least 100 feet above the Deschutes River,” Wershow said.
“Those boulders, very clearly to a geologist’s eye, were tumbled by a flood and put up there. So go hiking at Riley Ranch. Look at that hill and start thinking of what that flood must have looked like to be tumbling boulders the size of cars up to the top of that hill. It would have been just as impressive as the Missoula floods if on a slightly smaller scale,” Wershow said.
So move over, Noah.
“We’ve got our own epic flood story,” Wershow said.
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