Throughout the months of November and December 2024, the Los Angeles County Department of Public Works has been and will continue to reconstruct Altadena Drive between New York Dr. and the Midwick Gate. This project is occurring in an effort to improve asphalt conditions which have deteriorated after decades of storms and traffic. During construction, the main Eaton Canyon gate will remain open to ingress access only. All vehicles are required to exit the park onto New York Dr. via the overflow parking lot. Any vehicle caught bypassing barriers and closed gates attempting to exit through the main gate may be cited by county sheriffs’ officers.
In July, MyEatonCanyon.com reported on a single-car traffic accident by the Midwick Parking Pad that was due to excessive speeding and commented on the dangers of Altadena Dr. to Eaton Canyon visitors. According to the project outline, which is provided here, there are no plans to create safe crosswalks for pedestrians exiting the Eaton Canyon Main Entrance at this time. Comments on the project to team managers may be emailed to [email protected].
A young family darts across Altadena Dr. inbetween traffic, July 2024
Over the past 2 years, MyEatonCanyon.com has been monitoring changes to Eaton Canyon following the drenching winter 2023 rains, publishing articles on rain totals,tree sapling growth, and creek flow. Eaton Canyon has an exceedingly rare semi-arid Mediterranean climate type, in that not only do we have a winter wet season and summer dry season that is atypical throughout planet Earth, but our wet and dry seasons are far more pronounced than traditional Mediterranean climates. This fact puts Eaton Canyons’ ecology in an awkward position where it must be able to handle both several feet of rainfall in some years and 8+ month stretches without a single drop.
A forest in Eaton Canyon drying out significant between May 24, 2024 and August 14, 2024.
As we head into late autumn in Southern California, attention turns towards the equatorial East Pacific around and west of the Galapagos Islands. This particular part of the Pacific ocean undergoes periodic and regular sea surface temperature changes that impact the global weather in a phenomena we call the “El Nino Southern Oscillation” or “ENSO” for short. When ocean temperatures in this area are warmer than average, we call it El Nino. When they are cooler than average, we call this La Niña. These two episodes can last anywhere between 6 months and 3 years. La Niña conditions typically result in drier than average winters in California, though this is a generalization, not a rule. Famously wet years in the Golden State such as 2023 were La Niña years.
La Niña years more often than not generate persistent atmospheric ridging over or just west of California during the winter months, deflecting incoming Pacific rainstorms north into British Columbia. Meanwhile, El Nino years more often than not feature a strong subtropical jet stream that connects moisture between Hawai’i and the Southern California coast and can easily cut through those same ridges.
As of October 2024, the National Oceanic and Atmospheric Administration has a “La Niña Watch” in effect with cooler than average water temperatures in the equatorial east Pacific expected this winter. Earlier forecasts issued this past summer by NOAA called for more robust La Niña than we are currently seeing, and we’ve instead been hovering around neutral ENSO conditions. While conditions are still within the forecast envelope from last autumn, reality has been on the warm side.
ENSO conditions have trended on the upper end of ensemble forecasts over the past year.
Indeed, forecast models have begun calling for below average winter rainfall across the entire state, including Eaton Canyon. While these forecasts could very well be wrong, especially on a local level, optimism is not high for a wet winter 2025.
The CFSv2 model believes much drier than normal conditions will occur across California this winter.
This past Saturday, October 5th, 2024, an individual went hiking with their two dogs up the Sam Merrill Trail in Las Flores Canyon one mile west of Eaton Canyon while air temperatures were hovering in the low 90s. The individual hiked all the way up to the hotel ruins atop Echo Mountain before both dogs began suffering from heat illness. The hiker called 9-1-1 and the Altadena Mountain Rescue Team was dispatched to rescue them. However, before rescue crews could arrive, one of the dogs passed away.
Just 24 hours later on the evening of Sunday, October 6th, a 62-year old man with pre-existing health conditions hiking through Eaton Canyon collapsed of a heart attack brought on by heat illness. Despite performing CPR for 20 minutes, emergency crews were unable to resuscitate the man and he was declared dead at the scene. The temperature was 93.8°F at the time of the incident according to the nearby Southern California Edison weather station in the equestrian area.
Summer 2024 has finished with an average temperature of 78.97°F at the weather station in old town Pasadena, ranking as the 6th hottest summer on record out of 117 years. It also featured the area’s second hottest heat wave ever, reaching 114°F on September 6th. The heat continued into early October with a string of days in the low to mid 90s.
Recently, there has also been intense inversion layers at Eaton Canyon in the morning hours where cool air pools in the wash while heat collects at the ridge tops. These inversion layers form because cool air is innately more dense than warm air. Hikers beginning their climb at the Nature Center may experience temperatures rising from the low 60s all the way to 90°F once reaching Henninger Flats, even before sunrise. The following map shows temperatures throughout lower Eaton Canyon at 6:55 AM on the morning of Wednesday, October 2, 2024:
