Edgar McGregor

Edgar McGregor is a climatology senior at San Jose State University. He has collected litter from Eaton Canyon and other natural areas for over 1,400 days. Edgar's climate activist #EarthCleanUp account on Twitter has over 35,000 followers.

A blurry image of a night sky

100 Years Ago Atop Eaton Canyon, Edwin Hubble Proves The Universe Extends Far Beyond The Milky Way

It was a chilly, clear night in Eaton Canyon as the first Pacific rainstorm of the season approached. A light breeze rustled some Douglas Fir Pines on Mount Wilson while the skies overhead offered incredible views of the heavens. The moon was nowhere to be found. A large band of milky light dotted with secrets not yet discovered by humankind stretched high across the sky from one horizon to another. The year is 1923, and a certain astronomer on Mount Wilson is about to give all of humankind a reminder of just how small and insignificant we humans are.

Inside the brand new 101″ Mount Wilson Observatory Telescope, famed astronomer Edwin Hubble was peering into the night sky. He was aiming for a small cluster of light rising in the northeast over Mount San Antonio. On this night, Edwin Hubble was using a new method of measuring the distance of the stars called Leavitt’s Law. Its creator, Henrietta Swan Leavitt, was a scientist at Harvard who had studied a unique type of star called Cepheid variable stars. In 1908, she discovered that this type of star undergoes regular and predictable variations in brightness over time. By observing the period of a Cepheid variable star, astronomers could determine its intrinsic luminosity, and by comparing it to its apparent brightness, they could calculate the distance to that star. These stars have since earned the nickname “standard candles.” 

All around the world, astronomers who caught wind of this discovery began searching for those stars to calculate the true distances to them from Earth. Over the next 15 years, it became clear that the Milky Way was some 20,000+ parsecs in diameter. Edwin Hubble was one of those astronomers, and on the night of October 6, 1923, he discovered something odd. This method of determining the distance of the stars was seemingly not working for the small inconspicuous cluster he was staring at. His calculations showed that the Andromeda Nebula was 275,000 parsecs from the Sun, much further away than any Cepheid variable star previously discovered. After further investigations and confirmations, it was determined that he was not in error. Upon this discovery at Mount Wilson, Edwin Hubble realized that the nebula he was looking at was in fact the Andromeda Galaxy, a galaxy both different from our own and 250 million light years away. Before this discovery, scientists only had proof that the Milky Way existed, and nothing else. Now, we have proof that the Universe is far, far bigger. Henrietta Swan Leavitt died in 1921, never getting the chance to see her work completely reshape our understanding of the Universe. 

Eaton Canyon has a long history of water, homesteading, and tourism. However, its most significant contribution to the world is that it was here where we discovered the cosmos was incomprehensibly large. It was here atop Eaton Canyon that humankind once again was reminded that we are nothing against the grand scale of everything there is. In this age of fast moving headline news, pointless conflicts, and political drama, such a revelation is worth dwelling upon. 

PBS produced a short documentary at Mount Wilson that you can view here.

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2022-2023 Water Year Eaton Canyon’s Second Wettest Ever

The 2022-2023 water year in Eaton Canyon has ended as one of the most impressive water years of the past century. A copious number of storm systems well spread out throughout the entire season dumped a grand total of 4-5 feet of rain. In the past 116 years, only 2005 was able to drop more rain in Eaton Canyon. Included in this astounding year was well over 10 feet of snow on the highest peaks of Eaton Canyon, a landfalling tropical cyclone interrupting a hot summer, and absolutely no destructive flash flooding of any kind throughout all 12 months. Following the driest water year on record in 2021, in which Eaton Dam picked up only 5.63″, as well as the single longest, hottest, most extreme summer ever in 2022, the biological features of Eaton Canyon were suffering greatly. After 23 years of megadrought conditions across the western United States, this is precisely what Eaton Canyon needed to recover. 

Contrary to popular belief, megadroughts can not be ended in a single year even if record amounts of precipitation falls. Megadroughts are defined as ecologically destructive events in their own right, as they can cause entire species to go extinct, ecosystems to collapse, and ecological biomes to shift dramatically. While short-term extreme droughts can be sudden, megadroughts are relentless and span decades. Megadroughts can actually allow for native species to respond to changing climates. A minimum of 3 consecutive wet winters and cooler than average summers are needed to repair those damaged ecosystems and food chains. Some areas may require 5 such years to fully recover. This isn’t about reservoir levels or how good of a ski season it was, this is about the health of the entire ecosystem of this region of the world. In this era of rapid climate change, such a period of relief is less and less likely. Most summers in the 21st century are oppressive and lengthy. Even 2023 was an extremely hot summer for Southern California, with the July-August period being the second hottest July-August period ever behind only 2022. That being said, the canyon was struck by a landfalling tropical cyclone in mid-August that dumped 5″ – 7″ of drought-relieving rainfall. These tropical downpours kept the gains of the previous winter alive. More on Tropical Storm Hilary’s impact on Eaton Canyon can be found here

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Timeline of the 2022-2023 Eaton Canyon Water Year:

October 2022

Following a horrid summer that included our longest, most intense heat wave ever recorded in this area, October 2022 brought 0.3″ of rain to the canyon during a convective storm. Forecasts issued by long range meteorologists and climatologists called for a drier than average winter 2023 in California. This was not good news as the state was mired in both a 23-year megadrought and a 2-year long intense episode of exceptional drought.

November 2022

Moderately strong rainstorms began arriving in California in November, with the area picking up a healthy 3.29″. Signs that a wet winter ahead in California became more clear, and long-range forecasts for December-February were tuned.

December 2022

Occasional downpours continued into December, with another 4.97″ falling in the canyon. Drought impacts began to become mitigated, and the canyon responded with new growth.

January 2023

On New Year’s Day, the subtropical jet stream over the West Pacific became extremely powerful. When this happens, regions of Earth downstream can see rapidly changing weather daily for weeks on end, with troughs of low pressure and ridges of high pressure moving by quickly without ever stopping. Think of water shooting out of a hose that becomes wavy and rippled as it travels further away.

As a result of this powerful jet, a series of intense North Pacific storms began slamming into California at the start of the calendar year, dropping significant amounts of rainfall. Any time a ridge of high pressure tried to form, it immediately got knocked over by the next storm in line. Well over a foot of rain came down in Eaton Canyon in the first two weeks, totaling 13.45″. The strongest storm occurred on January 10th when 5.42″ fell in a single day. Several feet of snow fell in the upper canyon, reducing flash flood risk. Destructive flash flooding was fairly non-existent as most of the precipitation fell as snow.

Around the 15th, the clouds began to part. For the next 4 weeks, sunshine would prevail as the storm track retreated into Northern California. One system late in the month did produce 3/4ths of an inch, however. At this point, if the rainy season were over, we would land with one of the wettest winters of the 21st century.

February 2023

The first 3 weeks of February 2023 were relatively calm and sunny, allowing vegetation to really grow throughout the canyon. Western Sycamores thought winter was over, and began sprouting leaves. Some of the oldest Western Sycamores in the canyon knew what was up, however, and did not partake in the springtime festivities.

The lull ended around the 21st when a series of extremely cold, wet systems again swept the state. Heavy snowfall came down throughout the entire canyon, accumulating just a couple hundred feet above Eaton Wash. Snow fell across several low elevation Southern California communities. Torrential rain that lasted for days brought another 8.77″ to the canyon. Those Western Sycamores trees that had decided to leaf out in early February postponed spring and let all of their new foliage die in a second autumn. Since most trees were weeks into their spring growth, this was damaging to them.

March 2023

March arrived with chilly weather and yet more heavy rain evenly spread out throughout the month. Rain was observed on nearly half of all days in March, with little sunshine or warmth. 9.30″ fell in the canyon during the month, which is actually quite incredible for March.

April 2023

The storm series finally slowed in April, with only half an inch of rain being reported. Sunny skies and warm temperatures following a wet, cold winter allowed for considerable spring growth throughout the canyon.

May 2023

A handful of late season storms soaked the canyon yet again in early May, totalling another 2.09″. This rain helped keep vegetation growth strong during late spring.

June 2023

Not much rain fell in June, but extreme cloudiness prevailed across coastal Southern California, including at Eaton Canyon. While the upper portions of the canyon enjoyed cool, sunny, breezy skies, the lower 3/4ths of the canyon was mired in fog all month long. Much of this fog helped conifer trees create their own rain under their canopy, and as much as a few additional inches of rain fell in these parts of the canyon.

July 2023

The canyon got only a trace of rain in July, allowing the canyon to dry out and enjoy some sunshine. The area got very unlucky when remnants of Hurricane Eugene bypassed Los Angeles County on either side, missing the canyon but dropping up to 1.00″ to both the east and west.

August 2023

Very little rain is ever expected in August as the monsoon flow typically does not favor the south face of the San Gabriels. However, that all changed when a large complex of thunderstorms several hundred miles south of Acapulco, Mexico detonated into a juggernaut category 4 hurricane with an impressive 700 mile wide cloud field. The large hurricane, named Hilary, began racing directly for Southern California carrying huge amounts of tropical moisture. After juking out meteorologists who thought the system was headed inland through Baja California, Tropical Storm Hilary suddenly deviated to the left nearly one hundred miles and made landfall in Los Angeles County, California as a bonafide tropical storm, dumping over half a foot of rainfall on Eaton Canyon in a single day. The center passed over downtown and headed through La Crescenta into the Angeles National Forest, putting Eaton Canyon in the right eyewall. Fears of excessive rain rates did not come to fruition, but gusty winds and 24 hours of steady tropical downpours accompanied the tropical cyclone. Rare tropical convection was seen building over the canyon the day prior. This was Eaton Canyon’s second encounter with a landfalling tropical cyclone on record, as the 1938 Long Beach Tropical Storm also passed directly overhead.

September 2023

September is also usually hot and dry, but a series of marine layer events early in the month brought light rain to the canyon. Late in the month, a pair of thunderstorms moved over the canyon when a very early season winter storm impacted Southern California. 0.30″ of rain was reported.

A large green field with a mountain in the background

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Here Is Everything That Was Asked At The 2023 Eaton Canyon Community Meeting

On Friday, September 29th, 2023, the Los Angeles County Department of Parks and Recreation held an annual community meeting at the Eaton Canyon Nature Center to give locals a chance to voice their concerns about the park. About 30 people from the local community attended, many of whom were unaffiliated with the Nature Center. Those taking questions included Eaton Canyon Park Superintendent Lorraine Lazarus, Trails Division Coordinator Michelle O’Conner, Chief Deputy Alina Bokde, and Natural Areas Administrator Kim Bosell. 

What follows is a rough outline of which questions were asked by community members and how the county responded. Also included is some context to the topic at hand when needed. Please note that these are not exact quotes from either the participant or the county, but general paraphrasing. 

Click on each individual topic below to see what was discussed.

Participant: Many years ago, there was a rigorous volunteer effort to remove the invasive Arundo Cane plant from the Eaton Canyon area. These volunteer efforts ended some time ago and the plant is surging in the canyon again, especially on the Mount Wilson Toll Road headed up to Henninger Flats. 

Context: Arundo Donax is a perennial cane species native to the greater Middle East region. It has become invasive in Oceania and subtropical North America where is takes over sandy, riparian habitats in the form of dense stands. 

County Response: We will look into the matter and determine if any specimens fall within our park boundary. Our conservation group will see if anything can be done.

Participant: It is time to install security cameras around the Eaton Canyon Nature Center. Park staff frequently have to close up at night in the dark, break-ins in the parking lot are regular, and it would be nice to see which bears are going through the trash cans.

County Response: The Los Angeles County Department of Parks and Recreation has spent $2,000,000 of our $276,000,000 annual budget on security cameras at various facilities. We will look into whether or not this is possible for the Eaton Canyon Nature Center.

Participant: I am a neighbor who lives just outside the main gate on Altadena Drive. Every weekend tons of trash is left behind by visitors in front of my house. I would like to see more of an effort to get this litter cleaned up.

County Response: We will make it a priority to have our staff clean up litter in front of neighbor’s houses, especially on the weekends.

Participant: I don’t think we should require those wishing to attend events make reservations online. Having online reservations adds an extra barrier for those without wifi access or can’t read English.

County Response: There is no reservation requirement to access the park, that was just a pandemic precaution to limit trail visitation. As part of our strategic plan, a complete website overhaul will occur sometime soon. Our current website does offer tutorials on how to navigate the site in both Spanish and Mandarin.

Participant: I also live next to the canyon, and I was wondering if we could have a sheriff’s deputy open the gates in the morning and close them at night on Mondays. I understand the staffing issues, but every Monday tons of people park in front of our houses and leave behind trash. We could install a crosswalk with a blinking light to force vehicles to yield to pedestrians who are crossing. People are coming down Altadena Drive going 50 MPH on a regular basis, and it is only a matter of time before someone gets hurt or killed. 

Context: Eaton Canyon is a soft close park, meaning while the gates may be closed to vehicle access, pedestrian access is never restricted. On Mondays, the park is closed and gates are locked, but people can still park on Altadena Drive and walk in. The Midwick, Pinecrest, Altadena Crest, and Station 66 entrances are never restricted, though Pinecrest was supposed to be.

County Response: We will look into the matter.

Participant: I am a naturalist in the canyon, and I am concerned about non-native trees taking over the natural area. These non natives do not belong here.

County Response: The county will make it a priority to remove non-native saplings around the park, as well as any sick or dead trees that may be a hazard to trail users or vehicles. However, if the non-native tree is already mature, we cannot remove it. A mature tree is defined as one that supports it’s own habitat. 

Participant: There is also a dead non-native pine tree at the main gate to the park the poses a threat to the power lines that go to the Nature Center. It’ll come down in a severe storm.

County Response: We will look into the removal of that dead tree.

Participant: I too am a neighbor in the area and I have a complaint about people parking in front of fire hydrants and driveways on Altadena Drive when visiting this park. I had a neighbor that got her driveway blocked in one day, so she called the sheriff’s department to come have the vehicle towed. The sheriff instead wrote the vehicle a ticket and then left. She still couldn’t get out.

County Response: We will look into the best solution to limit overflow onto Altadena Drive.

Participant: Will the new bathrooms be chemical or plumbed?

Context: New outdoor bathrooms will be built by the county where the porta potties are located today just beyond the main parking lot. They will be open even when the Nature Center is closed.

County Response: They will be plumbed. We are expected to begin construction in June 2024.

Participant: Henninger Flats is being neglected by the Forest Service, and everything is being emptied out of the Nature Center up there.

County response: While the area is still under county jurisdiction, that area is a part of LA County Fire which is a different department. We will look into it, but there isn’t much we can do.

Participant: The latest figures from the county from 2019 show that 600,000 people visit the park annually. This number has risen following the pandemic, and the Eaton Canyon Trail is frequently the #1 most popular trail in Southern California on AllTrails.com. Can we install a temporary car counter strip on the driveway to determine how many people are coming in and out of the park?

County Response: Los Angeles County Parks and Recreation is undergoing reorganization to better allocate funding to the parks that need them most. This funding will be based on both visitation and acreage. A Los Angeles County program dubbed “30×30” that aims to conserve 30% of coastal and natural lands by 2030 uses cellphone data within parks to determine visitation, and we may be able to apply that technique here.

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