The 2023 water year in Southern California has become one of the wettest years of the 21st century. Over 30″ of precipitation has fallen in the canyon so far, with more on the way. All of this heavy rain has taken its toll on Eaton Canyon’s popular trails, with several sections of the main Eaton Canyon Trail being damaged. All of the damaged sections are north of the Eaton Canyon Natural Area Park boundary in other government jurisdictions.

 

A storm in December 2021 severely damaged a section of the Walnut Canyon Trail, allowing huge amounts of water to flow into a smaller canyon that normally wouldn’t see as much flow. This water drains on to the main Eaton Canyon Trail which was severely damaged during the January 10, 2023 storm. Subsequent storms have made the situation worse. The location of this trail rut is 34.18611139942555, -118.1007962997867

The 2005 flash flood that struck Eaton Canyon was one of the largest floods in the past century. Part of the main trail was washed out, and a ~25′ dirt and sandstone wall that was sculpted by this flood remains there to this day. Too much rain this past winter caused part of this sandstone wall to collapse on the main Eaton Canyon Trail during the January 10, 2023 storm.  About 80% of the trail was blocked by mud. It is still safe for hikers to bypass, but it is not possible for emergency vehicles to circumvent. The location of this mudslide is 34.18989461871701, -118.10316768066636

Lorraine Lazarus, Eaton Canyon Natural Area’s Superintendent, inspected damage to the trail on Monday, February 27th. A work order has been submitted and the county is planning to repair the trail rut following the current storm series. There has been no update on the mudslide further up the trail.

Photos: @ Edgar McGregor,  @ Susan Hopkins 

---

Photo: © Dave Szamet

A powerful Pacific storm made landfall in Southern California on Friday, February 24, 2023, and Eaton Canyon took the brunt of the system. The storm brought a whopping 40″ (3 feet, 4 inches) of snow to Mount Wilson according to the National Weather Service in Oxnard. At the bottom of the canyon, Eaton Dam reported 7.93″ of precipitation for the entire event, bringing the water year’s rain total to 29.73″ of accumulated precipitation. This makes the 2022-2023 water year the wettest rain year in the canyon since since 2005 when 70″ fell in lower Eaton Canyon.

Snow levels were reported to be down to 2,500′ at times, with up to an inch of snow falling at Henninger Flats. Old Pasadena reported 8.11″ of rain, 7.49″ of which fell during 48-hour period from February 24-25th. This makes the 2023 #SouthernCaliforniaBlizzard the 11th wettest 2-day period in Pasadena’s 118 year long weather record book. Flash flooding within Eaton Canyon itself was limited due to low snow elevations and the lack of any particularly heavy downpours throughout the system. It is increasingly obvious that rain rates, not necessarily rain accumulations, are the most important factor for producing dangerous flash flooding within the canyon. The December 14, 2021, January 10, 2023, and February 24, 2023 storms all brought 6″ – 8″ of rain to Eaton Canyon, but that precipitation fell in a much shorter amount of time during the December 14, 2021 storm and resulted in a much more significant flash flood.

Maximum wind gusts included 34 MPH at the Pinecrest Gate, 50 MPH at Henninger Flats, 74 MPH at Mount Disappointment, and 86 MPH at Barley Flats Road behind Eaton Canyon along Hwy 2 in the Angeles National Forest.

The Altadena Mountain Rescue Team (AMRT) reported that 2 individuals were trapped in the canyon after dark on the 25th as the trails were too slippery to hike up. Once again, we do not advise hiking in Eaton Canyon during inclement weather. While rescues happen at all times of the year, rescues are most common in winter when inexperienced hikers underestimate the power of mother nature. Always check the forecast and let others know where you are going and when you’ll be back.

More images of our incredible snowstorm all courtesy of AlertCalifornia webcams:

---

The 2022-2023 winter will go down in southern California as being a cool and wet winter, a rarity among the rapidly warming desert southwest. During the 21-day period stretching from December 27 through January 16th, Eaton Canyon picked up an incredible 13.31″ of rainfall. Immediate storm impacts to the park from this event were outlined in a previous article located here. 

January 2023 in downtown Pasadena picked up 13.45″ of rainfall, our wettest month in over 13 years. Of all the winters of the past decade, only the 2018-2019 water year saw more rainfall than the 2022-2023 water year has, but we still have quite a way to go before the season is over. A very green spring is anticipated this year as a result of all the rain. Be sure to check out all the flowers, mushrooms and new growth in the canyon!

Here is a chart showing monthly precipitation in Old Pasadena since the start of the 21st century:

---