2022-2023 Water Year Average Reached, Eaton Dam Up To 21.24″ since October 1st

Since October 1, 2022, Eaton Canyon has seen 21.24″ of rainfall, 13.28″ of which fell during the December 26 – January 16 time frame.  Rainfall in the canyon is measured at Eaton Dam, just south of the reservoir. Eaton Canyon is not known for it’s excess water, with the river not frequently flowing past the canyon mouth for more than a few months out the year. Plants throughout Eaton Canyon are adapted to drought, with even our native coffee ferns being able to go months without a drink of water. That being said, compounding drought, human encroachment, invasive species, and hotter summer temperatures are endangering some species in the canyon.

Another flash flood struck Eaton Canyon on the morning of January 10, 2023 after a whopping 5.14″ fell on the canyon. It was our 48th wettest 2-day period since 1908. The flood was nearly as large as one that occurred on December 14, 2021. Here are notable changes that occurred within the wash:

A significant landslide occurred 0.4mi from the bridge, just downstream and around the corner from the Eaton Canyon Waterfall. A negatively sloped wall came down, and several tons of rock and debris dammed up the river. The flash flood was still in progress when the cliff came apart, and copious amounts of sand and gravel backed up behind the rock slide, immediately filling the new watering hole that was just created. (34.19543946797055, -118.10191245661396)

A downed Mexican Fan Palm that was deposited at a location near the Walnut Canyon / Main trail intersection (34.18561917195616, -118.10078717633861) during the December 14, 2021 flood, was moved downstream to a location due east of the main Eaton Canyon sign at the north end of the main parking lot during the January 10, 2023 flood. (34.178346250196846, -118.09578901171221). These two locations are 0.65 miles apart from each other! Observers noted the palm tree floating past the main trail’s first crossing at 10:29 AM on the morning of the 10th. The palm tree was moving at just over 10 MPH.

Mule Fat (Baccharis salicifolia) is the species of plant that typically lines the riverbed in our wash. It is more hardy against flash floods than your average plant, but it too occasionally falls victim. Two areas on the right side of the riverbed between the Midwick entrance and the first crossing were significantly eroded away with this latest flood, ripping out tons of mule fat and lots of boulders that kept them in place.  The two locations were nearby each other, once at 34.18293865515512, -118.09807790466684 and again at 34.18321650828237, -118.09888545820216.

This eroding riverside also destroyed a temporary waterfall that was filmed in the Trail Magic article “Slow-motion waterfall,” which can be found here.