Historic Yellowstone Flood

You have probably heard about the historic Yellowstone flood that closed Yellowstone National Park earlier in June of 2022. On top of heavy rains, warm temperatures caused massive snow melt. The result was that Yellowstone River and its tributaries overflowed their banks, washed out roads in the park, and washed away buildings in the area. Thousands of people had to be evacuated from the park, and it was closed. The northern part of the park suffered the worst damage and is still closed at this time.

The Yellowstone River is the longest free-flowing river in the lower 48 United States. It flows for almost 700 miles without any dams to hold it back. Humans see this flooding as a disaster that will take years and millions of dollars to correct. However, from the standpoint of trees and animals, the flooding is a blessing. Cottonwood and willow trees along the river were declining. They serve to provide shade and shelter for bison, gray wolves, and grizzly bears. The flooding provided new moist soil and carried seeds, allowing new trees to sprout and grow.

When rivers don’t have an opportunity to overflow their banks, erosion deepens the channels, invasive plant species grow along the banks, and the floodplain wetlands dry up. When rivers run wild and overflow their banks, the surrounding wetlands store water and provide habitats for many birds and mammals. In addition, a raging river spreads new soil across the floodplain, reshaping and renewing the land. Scott Bosse, the director of American River’s Northern Rockies office, said, “As humans, we often think that floods are disastrous, and fires are disastrous, but they’re really only disastrous because we put human lives and property in harm’s way. They’re not disastrous from an ecological standpoint. Quite the contrary, they’re healthy for rivers, and especially for a river like the Yellowstone.”

This historic Yellowstone flood is not all bad. As far as the animals are concerned, they are probably relieved to have fewer humans around. The native cutthroat trout in the Yellowstone river can find new access to tributaries to spawn. At the same time, the introduced rainbow trout have had their eggs and fry washed away by the raging waters. The scouring of the river washed up a supply of invertebrates to provide meals for fish and birds. Ospreys, eagles, American dippers, and river otters benefit from a new food supply.

Meanwhile, the historic Yellowstone flood allows cottonwood and willow trees to release their seeds into the wet sandy soil to germinate. Cottonwoods are the dominant trees along the Yellowstone River, and the new trees will benefit breeding birds in the future. Because of the added soil moisture, the flood waters also benefit the grazing animals by giving them more plants to graze on.

Floods can benefit the ecosystem, but humans often build roads, homes, and other structures in floodplains. Or they build homes downstream from dams that have the potential to break and cause a worse flood. God gave us the responsibility to care for the Earth. To do that, we must first respect it and understand how natural systems work. In the long term, the Yellowstone River ecosystem and its tributaries benefit from the historic Yellowstone flood.

— Roland Earnst © 2022

Reference: National Geographic “Historic Yellowstone Flooding Brings Renewal Despite Destruction” by S.J. Keller