SGM: The Numbers

Water Resources
Abbreviations and Sources

This page gives the basic numbers about the SGM and the ANF for quick reference. If you came to this page looking for some numbers that you don't find, email us and we'll probably add them if we can find them.


San Gabriel Timberland Reserve established: 12/20/1892 (TOTA)

Names for the Forest Unit:
    San Gabriel Timberland Reserve, 1892
    San Gabriel National Forest, 1907
    Angeles National Forest, 1908.

Names for the Mountains: Both "Sierra Madre" and "San Gabriels" were in use simultaneously in the earliest accounts for the "mountains behind the Mission". The "Sierra Madre" was usually a broader term that included the southern mountains of California as well as those in Mexico. But the L.A. Times used "Sierra Madre" to refer to the San Gabriels as late as 1886. In 1927, the U.S. Board on Geographic Names ruled in favor of "San Gabriels" as the official name for the mountains. (SG)
The range in the 1948 movie Treasure of the Sierra Madre was in Mexico.

Forest Service Budget for the ANF:
   Drug enforcement: $340,000 / year "in the forests of Southern California" for 9 federal officers and two investigators. (LAT 8/30/99, B3)

Wilderness Areas: 3 totaling 92,276 acres, 14% of the total ANF area, roughly the same as the national 18% average for Forest Service property (34.7 out of 192 million acres).
The ANF Wilderness Areas are San Gabriel (36,118 acres, 1932), Cucamonga (12,781 acres; 1984), and Sheep Mountain Wilderness (43,377 acres; 1984) (TOTA, San Gabriels, California Scenic Drives, LAT 10/13/99, A11)

ANF districts: see Forest Offices and ANF Forest Service Offices and Districts.


Numbers of Large Animals: ~2,200 (see below) to ~5,500 mule deer (ANF MP); numerous coyotes; ~150-500 black bears; 35-100 bighorn sheep (Daily Breeze, 3/21/99; LAT 11/12/99, B6); 40-50 mountain lions (TOTA).

Except for the bighorn sheep, the numbers are quite uncertain since no regular census is conducted counting these animals. The bighorn sheep have been declining drastically from more than 700 in the 1980s (LAT 11/12/99, B6). The decline is thought to be due to mountain lion predation.

(Recently) Extinct Large Animals: California condor (~1900), California grizzly bear (~1900) (TOTA); pronghorn antelope (AALAC)

(Reputedly) Largest Grizzly Bear in California: 2,350 pounds, Soledad Canyon, shot in 1873 (SG). The grizzlies supposedly grew larger in southern California because they spent less time in hibernation.

Introduced Large Animals: Black bears, 1933. "Eleven black bears were introduced into the San Gabriel Mountains 'near Crystal Lake' in November 1933 from the Sierra Nevada (Burghduff, 1935)." in Mammals of the San Gabriels by Terry A. Vaughn.

Number of Animal Species:

AnimalNumber of SpeciesNumber of Special Concern,
Threatened or Endangered
(more info
about lizards)


Annual precipitation: Varies as a function of elevation, slope orientation (north or south-facing), and general location (east-west and north-south). Examples from south to north:

LocationElevation (')Rainfall (")
Mt. Wilson5,71035
Table Mountain7,51621
(USGS, Climate and Man; Yearbook of Agriculture, 1941; Weather of Southern California, A Natural History of California)

Greatest Amount of Rainfall in One Minute in California: 0.65 inch at Opid's Camp, April 5, 1926 (CA)

Greatest Amount of Rainfall in One Day in California:

RankStationDateAmount (")
2Lytle Creek PH01/25/6924.92
3Cogswell Dam01/22/4323.12
4Opid's Camp01/22/4322.32
5Lytle Creek RS01/25/6921.61
Source: Historic Rainstorms in California, James Goodridge

Average Annual Snowfall at Ski Resorts:

Elevation (')
Snowfall (")Source, Where Numbers Differ
Ski Sunrise
at Table Mtn
at Kratka Ridge
Mt. Waterman8,000130 
Mountain High8,200120
Winternet: Mountain High Ski Area
Mountain High Resort Facts
Mt. Baldy8,600150 
Other Sources: 10,000 Inns, Ski Agent, and GoSki

Greatest Amount Of Snowfall In One Day At Mt. Wilson Since 1949: 16 inches on December 29, 1974 (Western Regional Climate Center)

Greatest Snowdepth At Mt. Wilson Since 1949: 80 inches on January 8, 1974 (WRCC)

Most Days With Enough Natural Snow For Skiing In A Season At Mt. Waterman: 90. Lynn Newcomb, the long-time owner of Mt. Waterman, estimates that snow-making equipment would "guarantee 120 days per year". (LAT 10/9/99, C5)

Highest Temperature At Mt. Wilson Since 1949: 99° F on July 14, 1972 (WRCC)

Lowest Temperature At Mt. Wilson Since 1949: 9° F on January 26, 1969 (WRCC)


Area: 693,667 acres within the outer boundaries (TOTA), equal to 1,084 square miles, with 652,704 acres of Forest land (SC). The shape is to a close approximation a triangle of sides 49 miles along the east-west bottom, 62 miles along the northwest-southeast western side, and 102 miles along the WNW - SSE northeastern side. This triangle has an amazingly-close area of 711,000 acres.
It is not by chance that the ANF is shaped like a triangle. The San Andreas Fault forms the longest side of the triangle; the Sierra Madre Fault System forms the bottom side; and the San Gabriel Fault forms the western side. These faults not only define the San Gabriel Mountains, the faults created and continue to create the mountains by uplift along the faults on the San Gabriel Mountain side.

Elevations: ~800' at the mouth of San Gabriel Canyon to 10,064' at Baldy (Mount San Antonio). (USGS)

Highest Elevation Along Major Highways, sorted by elevation:

HighwayHighest Elevation (')Location
The Angeles Crest Highway (SR2)7,903Dawson Saddle
Angeles Forest Highway (N-3)4,910Mill Creek Summit
I-154,259Cajon Summit
I-54,175Tejon Pass
Antelope Valley Freeway (SR-14)3,258Escondido Summit

Distribution of Slope Angles:

AnglePercent of ANF
0 - 20%  4
21 - 40%  4
41 - 60% 25
over 60% 67

Rate of Degradation of the San Gabriel Mountains:

This drainage area produces an average of 359,219 cubic yards per square mile per year. This indicates that, during the period of record, the rate of degradation has been 0.06 inch per year. If debris production continued at this rate, 5,000' would be eroded in one million years. It has been estimated that the rate of denudation for the entire United States is about one foot per 9,000 years. The figures obtained from three of the 49 basins in the San Gabriel Mountains indicate a denudation of one foot per 200 years, 45 times the average estimated for the United States.

quoted from Geology of Parts of the Azusa and Mount Wilson Quadrangles, San Gabriel, Mountains, Los Angeles County, California, page 16, Douglas M. Morton, Special Report 105, California Division of Mines and Geology, 1973

Vertical Drop at Ski Resorts:

LocationDrop (')
Mt. Baldy2,100
Mountain High1,800
Mt. Waterman1,200
Ski Sunrise816
Sources: 10,000 Inns, Ski Agent, and GoSki

Deepest Canyon: 5,227', the Narrows of the East Fork of the San Gabriel River. The elevation changes from 2,780' at the bottom of the Narrows to 8,007' Iron Mountain at the top of the east wall of the Narrows, along a horizontal distance of only 1.8 miles. The average slope from the bottom to the 7,000' contour is an amazing 4,220' in 1.06 miles, or 75%. This is the deepest gorge in Southern California. (USGS, AALAC)

Predominant Rock Type: 70% of exposed surface is Mesozoic granitic rock, typically 61-84 million years old (mya), but the Mt. Lowe and Parker Mountain granitic rocks are 220 - 245 mya. (GC)

Oldest Rocks:

RockAge in
Millions of Years (mya)
San Gabriel anorthosite1,220
Mendenhall gneiss1,045
augen gneiss1,700

The 1.7 billion year old augen gneiss is the oldest dated rock in California. All three of these rocks, which make up much of the San Gabriels, are much older than typical California rocks. For example, the Sierra Nevada rocks, 100 - 500 mya, are barely middle-aged in comparison, and the Coast Range rocks, up to 100 mya, are mere babes. Only the Mojave Desert contains rocks of comparable age to the San Gabriels. (GC)

Anorthosite is a common rock on the Moon's highlands, and lunar astronauts trained here to prepare them for sampling the Moon's rocks.

Youngest Rocks: The Cajon Rocks in the Cajon pass and the Punchbowl formation at the Devil's Punchbowl are 7-20 mya. (GC)

Vegetation Cover:

Type of VegetationPercent of ANF
coastal sage scrub and chamise chaparral50
mixed and semi-desert chaparral28
conifer woodland forest17
pinyon - juniper forest1

Number of Rare Plants: Over 20, including Mount Gleason paintbrush, lemon lily, and the short-jointed beavertail cactus. (California's Wild Gardens)

Number of species of vascular plants: ~1,200 (California's Wild Gardens)


California State Historical Landmarks in the Angeles National Forest/San Gabriel Mountains
Expanded Version with Comments and Location
Data Source: California State Historical Landmarks in Los Angeles County

1804556Rancho San FranciscoNewhall
1842168Oak of the Golden DreamSan Fernando
1851577Mormon Trail MonumentTelegraph Peak
1855688Lyons Station Stagecoach StopNewhall
18621006Beale's Cut Stagecoach PassOat Mountain
1875172Pioneer Oil RefineryNewhall
1876516Well, CSO 4 (Pico 4)San Fernando
1876590LangMint Canyon
1892514Pomona Water PowerplantMt.Baldy
1892717The Angeles National ForestCondor Peak
1900632Old Short CutMt. Wilson
1913653The CascadesMint Canyon
1928919St. Francis Dam Disaster SiteWarm Springs Mtn.


Record Largest Trees by Species:
Tree SpeciesRecordDiameter (')StatusSource
Western JuniperWorld15.15??An Island Called California
Canyon Live OakWorld11.88burned outTOTA
White FirANF9.50cut downGR
Sugar PineSouthern California7.50fallen overTOTA
Bigcone SpruceNational7.5??Exceptional Trees of Los Angeles by Donald R. Hodel

Tallest Tree: sugar pine (GR)

Oldest Tree: more than 3,000 years, the estimated age of a western juniper in Icehouse Canyon, (Roadside Plants of Southern California) OR about 2,000 years, a limber pine on Mt. Baden-Powell (TOTA, Trip 81; Exceptional Trees of Los Angeles by Donald R. Hodel) and others there to Mt. Burnham and Throop Peak at timberline (SC). One of the largest limber trees is named the Waldron Tree, and has been dated to "older than 1,200 years" (A Natural History of California)

Most Common Coniferous Tree (at all elevations): Jeffrey pine (GR)

Heaviest Pine Cone: up to 9 pounds, Coulter pine (CFW)

Longest Pine Cone: 10 - 24 inches, sugar pine (CFW)

Longest Pine Needles: up to 12 inches, Coulter pine (CFW)

Largest Maple Leaf: 12 inches in diameter, bigleaf maple (Trees of North America by C. Frank Brockman, New York, Golden Press, 1986, page 214)


Number of Visitors: 3.5 ± 0.3 million per year, including 0.11 million visits to Wilderness areas, in the year 2000. (National Visitor Use Monitoring Results)

This number is only about 10% of the inflated visitor numbers reported for decades - e.g., 32-35 million per year for the ANF (TOTA, SDUT 1/7/96, A3). The new numbers came from an independent academic survey led by Dr. Jerrell Ross Richer by California State University of San Bernardino. Previously, the loose system used by the Forest Service could count the same visitor 4-5 times if they visited 4-5 different facilities, as well as counting people traveling through the Forests who just stopped to use a bathroom. "Mostly, we guessed," said Sue Kocis, a leader of the Forest Service's new National Visitor Use Monitoring Project.

Similar accurate surveys will now be done in one-fourth of the Forests each year. (The Oregonian, 11/15/98)

The Angeles Forest receives more visitors annually than any other unit of the national forest system. (Angeles Volunteer News, December 1998)
Reason for visit, in order of popularity (SC):

  1. Sightseers ("two-fifths" of all visitors)
  2. Picnickers
  3. Winter sports participants

Reason for visit, estimated from interviews with 1535 visitors (out of 1828 total interview attempts) in the year 2000:

Of those recreating, the top activities were:

(Totals are more than 100% since some people were doing several of the activities.)

Source for both of the previous two items: National Visitor Use Monitoring Results.

425,000 skiers visited Mountain High in the 1997-98 extremely-heavy snowfall season, and 385,000 in the 1998-99 extremely-light snowfall season. (LAT 10/9/99, C5)

Number of Lifts at Ski Resorts:

Ski ResortLifts
Mountain High10
Mt. Baldy4
Ski Sunrise4
Mt. Waterman3
Sources: 10,000 Inns, Ski Agent, and GoSki

Number Of Emergency Calls Per Year: ~1,100 (LAT 7/13/95, B4)

Number Of Rescue Missions Per Year: ~300 (LAT 2/26/99)

Number of Incidents Per Year: 6 deaths, 17 nonfatal falls, 18 incidents of people stuck on cliffs, 7 mountain bike accidents, 76 motorcycle accidents and 44 reports of lost hikers, all in 1994. (LAT 7/13/95, B4)

Number of "Rave" Parties: Snowcrest Snowpark, the former Kratka Ridge ski resort, has hosted ~6 rave parties, each with about 80 security guards and ~5,000 attendees, lining ~10 miles of SR2 with parked cars. After the deaths of five teenagers in summer, 1999, Snowcrest has suspended hosting further rave parties, helped in its decision by a suspension in permits for such parties from the Forest Service. (LAT 8/30/99, B1; LAT 10/9/99, C5)

Roads: 988 miles (TOTA), including 261 miles designated for OHV (ANF map).
   First road all the way across the backbone of the San Gabriels: The Edison pole line road from Vincent to Eagle Rock, 1925 to 1926. (SG)
   The Angeles Crest Highway, SR2, is 66 miles long from I-210 in La Cañada to Mountain Top Junction at SR-138. The highway was originally envisioned in 1912 as "the most scenic and picturesque mountain road in the state", but the need for a road for fire-fighting was at least equally important. Funds were allocated beginning in 1919, construction began in 1929, continuing piece by piece until 1956, except from 1941 to 1946 during WWII.
The road is typically closed to car traffic and unplowed between Islip Saddle and Big Pines after the first snowfall (typically October through December) until May or June. Recent opening dates have been 6/12/92, ~7/1/98 and ~5/15/99. (California Scenic Drives, SG)
   The Angeles Forest Highway (N-3), aka the Palmdale Cut-Off, was surveyed in 1913, approved in 1928 to roughly follow the Edison pole line road, and built from 1932 to 1941.
   Big Tujunga Canyon Road was built from 1952 to 1958. The upper Big Tujunga Bridge is the largest single arch structure in the county, standing 130' above the stream. (SG)
   San Gabriel Canyon Road (SR-39) opened in 1961, was closed regularly due to landslides on the west face of Mount Islip, and closed permanently in 1978, with Mother Nature declared the victor. (SG)
   The Bridge to Nowhere was part of a road up the East Fork of the San Gabriel River built in 1929 to 1938, when most of the road was destroyed by a rainstorm, leaving the bridge stranded. The Road to Nowhere was another attempt made from 1954 to 1969, stopped this time by budget-cutters and environmentalists. (SG)

Trails: "775 miles of riding and hiking trails" (TOTA) or "557 miles of hiking and equestrian trails", including 73 miles of National Recreation Trails and 176 miles of the Pacific Crest Trail (ANF site).

Other: 59 campgrounds, 7 group campgrounds, 36 picnic areas, 8 resorts, 24 organizational camps, 707 summer residences, and 5 winter sports areas, 6 visitor centers (Chilao, Grassy Hollow, Mt. Baldy Village, Crystal Lake, Big Pines and Vista del Lago), 2 target shooting areas and 3 historical heritage sites (ANF, ANF map, TOTA).

California's First Gold Rush: 1842, Placerita Canyon (SG)

Amount of Gold Discovered and Removed: total from ?# - 19xx, 75 pounds per year in the 1990s. About 10 people use gasoline-powered "dredges" daily to search for gold, and up to 40 people are weekend prospectors. (LAT 7/31/99, B1.)

Number Of Marijuana Plantations Discovered Each Year: 15-20, with 10-15 thousand plants removed every year, an estimated one-third of what is grown, based on finding crop remains after harvest. (SDUT 1/7/96, A3; LAT 8/30/99, B3)

Water Resources

Natural Lakes: 4: Crystal Lake, Elizabeth Lake, Jackson Lake and Lake Hughes, all sag ponds along the San Andreas Fault except for Crystal Lake (ANF map, San Andreas Field Trip)

Reservoirs: 13: Big Dalton Reservoir, Big Tujunga Dam, Bouquet Reservoir, Cogswell Reservoir, Lake Castaic*, Lake Piru, Little Rock Reservoir*, Morris Reservoir, Pacoima Reservoir, Pyramid Lake*, San Dimas Reservoir, Santa Anita Dam, San Gabriel Reservoir* (ANF map)
* Public reservoirs

Flood Control Structures (Debris Dams): More than 123 (Los Angeles River, Gumprecht, quoted in LAT 8/15/99, Book Review, 3.)

Major River Systems: 1, San Gabriel River, 65 miles from headwaters to mouth, with an average annual runoff of 148,000 acre/feet. (CA)

Perennial Streams: 7; Big Tujunga River, Bouquet Canyon, Arroyo Seco, Big Santa Anita Canyon, Big and Little Rock Creeks, San Gabriel River and San Antonio Canyon (ANF map); totalling 240 miles in length (AALAC); 189 miles of fishing streams (SC)

Only Stream in L.A. County Selected For Consideration As A Federally-Designated Wild and Scenic River: the middle section of Piru Creek at the northwestern boundary of the ANF (AALAC)

Highest Waterfalls: Alpine Falls (aka Chapman Falls), >130'; Leontine Falls, 105-120'; Thalehaha Falls, 80-112'; San Antonio Falls, 100'. (Caution: this list is probably incomplete. See SGM: The Waterfalls)

Location of Most Waterfalls: It is no accident that most of the waterfalls are along the front range, since recent uplift of the San Gabriel Mountains relative to the L.A. Basin has created them. As a result, they are all roughly at the same distance from the Sierra Madre Fault System.

Abbreviations and Sources

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Copyright © 1999-2001 by Tom Chester and Jane Strong.
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Updated 26 October 2005.