SoylentNews is people
SoylentNews
Journal by khallow
There's a huge bunch of flooding in Yellowstone National Park. It started with heavy rain yesterday that led to a mass melting of the high altitude snowpack. Net result is instant 100 year floods on multiple rivers through Wyoming and Montana. Here's a video of some of the flooding. That video shows the North Entrance road which comes into the park from the northwest side (starting at a town, Gardiner, Montana) and runs along side the Gardiner River, which is a minor river which dumps into the Yellowstone River - the latter is the largest tributary of the Missouri River.
Anyway, this shows the crazy erosion power of a mountain river that's flooding. With normal spring melt level (which is when the river is at its routine highest seasonally), the river moderately erodes its banks, but hasn't threatened the road in decades. But with this higher level of flooding, the road has been completely cut through in five places in the video. In addition to the road bridge (which is still in place in the video), there was a trail bridge about a mile north of the road bridge which was washed out too (it's almost center in the last frame, you can see a pull out on the right between road and river with a trail on both sides of the river - the bridge would have been in between the trail parts).
Finally, I linked to the map so you can see what the stretch looked like before the flooding. The helicopter is flying from south to north along the road. By coincidence, the video starts about where the tag is on the map.
Anyway, this shows the crazy erosion power of a mountain river that's flooding. With normal spring melt level (which is when the river is at its routine highest seasonally), the river moderately erodes its banks, but hasn't threatened the road in decades. But with this higher level of flooding, the road has been completely cut through in five places in the video. In addition to the road bridge (which is still in place in the video), there was a trail bridge about a mile north of the road bridge which was washed out too (it's almost center in the last frame, you can see a pull out on the right between road and river with a trail on both sides of the river - the bridge would have been in between the trail parts).
Finally, I linked to the map so you can see what the stretch looked like before the flooding. The helicopter is flying from south to north along the road. By coincidence, the video starts about where the tag is on the map.
Reply to: 2019 Nebraska floods
Post Comment
Do not use if foil seal is broken.
(Score: 4, Informative) by dalek on Wednesday June 15 2022, @08:10AM
This sounds all too familiar to me, unfortunately. Back in 2019, there was a similar situation in eastern Nebraska. The results were devastating.
On February 23, there was a blizzard that dropped many inches of snow. There were other snow events in central and eastern Nebraska after that. Temperatures were generally quite cold for that time of year, maintaining significant snow depth into mid-March. The cold temperatures increased the amount of ice on the rivers.
Then on March 13, there was a powerful extratropical cyclone that produced heavy rain over much of area that had a lot of snow on the ground. Two to three inches of precipitation fell, much of it as rain, melting the snow that had been on the ground. Because of the snow cover and the cold temperatures, the ground was frozen, so virtually all of the melted snow and the rain was runoff instead of being absorbed into the ground. Water levels rose rapidly, and the flooding was exacerbated by ice jams on the rivers. The damage in eastern Nebraska and even into western Iowa was catastrophic. A dam was breached on the Niobrara River, and there were levee breaches even on the Missouri River.
One of the largest cities in the area, Lincoln, actually had to order residents to greatly reduce water usage because the city was running low on water. Lincoln doesn't get its water from rivers like the Platte or the Missouri. Instead, much of the water is drawn from the Ogallala Aquifer by pumps near the Platte River. The damage from the flooding knocked out electricity to the pumps, causing a water shortage amid the extreme flooding.
Generally when you have heavy rain rapidly melting a lot of snow, you're going to have the potential for flooding. If temperatures have been cold, and the ground is frozen, it's going to make the situation worse because very little of the water will be absorbed into the ground. In 2019, there was enough heavy precipitation and melted snow over a large enough area to create a pulse of water that caused record flooding on the Missouri River from the mouth of the Platte River to St. Joseph and moderate flooding all the way to St. Louis.