Slow-Motion Floods
To us, flash floods are a frightening product of powerful North Pacific rainstorms. To Eaton Canyon, flash floods are a way of life. For over six million years, these floods have been carving Eaton Canyon out of the San Gabriel Mountains. They push boulders around, take tree logs for a one-way journey downstream, and remind plants not to grow at the canyon’s lowest point. Most floods are just a spectacle, others can be momentous. But every now and again, these floods can be sovereign.
Within the last 100 years, at least five sovereign floods have decimated Eaton Canyon:
- March 1938
- January 1943
- January 1969
- February 1980
- January 2005
All of them reshaped the wash and removed 95 percent of trees growing beside the creek.
During the biggest floods of the century, as much as 20 inches of precipitation fell on lower Eaton Canyon and up to 40 inches of precipitation fell on the mountains above in just 10 days. On January 22, 1943, Hogee’s Camp on the other side of Mount Wilson reported 25.83 inches of rainfall in a single 24-hour period, a western U.S. record.
Another catastrophic flood will hit someday soon. It is only a matter of time.
Ever notice very large pine tree logs scattered around Eaton Canyon’s wash? Those are big-cone Douglas Fir trees that grew miles upstream at the top of Mount Wilson. Only the largest floods of the century are able to deposit these logs within Eaton Wash. They serve as great proxy data about how large the floods can be in this canyon. There are over 100 logs in the wash, the largest of which has a circumference of 179 inches.
This video shows flash flooding in slow motion following the January 9-10, 2023 storm that dropped 5½-12 inches of rain in Eaton Canyon.
Videography and Editing: © Edgar McGregor
Music: “Soaring” by Kevin MacLeod
License (CC BY 4.0): https://filmmusic.io/standard-license
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