By Joe Streetman
The Journal of San Diego History
San Diego History Center Quarterly
Winter 2016, Volume 62, Number 1
The Mountain Springs Grade: Conquering San Diego’s Mountain Barrier to Commerce with the East (PDF)
Except for an inconvenient accident of geography, the all-weather harbor of San Diego would have been a bustling hub of commerce in 1849-1861 linking the South- west to the booming gold fields of northern California. San Diego lay only 170 miles almost due west of Fort Yuma, located at the only practicable crossing of the Colorado River within 200 miles. During the US-Mexican War and the Gold Rush that soon followed, San Diego’s harbor should have been crowded with the flood of troops, gold-rushers, emigrants, and military supplies passing through Yuma, to connect with steamships from the East bound for San Francisco and the gold fields.
During this time, however, San Diego’s residents slumbered on beside an empty bay because of that one inconvenient geographic fact—about 80 miles to the east there was a then-impenetrable mountain barrier to wagon travel. That barrier made it much easier for horse or wagon travelers from the east to go to Los Angeles and its fair-weather San Pedro harbor than to San Diego.1 San Pedro, moreover, was 120 miles closer to San Francisco and the gold fields.
Today, Interstate 8 penetrates the barrier over the Mountain Springs Grade in the Jacumba Pass. The federal government built Interstate 8 grade in the 1970s at a cost of about one million dollars per mile. Its goal was to connect all major cities with high-speed freeways. But in the mid-1800s, there were no federal or state charters to build roads. If San Diego wanted a road, it had to build one out of its own resources.
The first stagecoach roads over the barrier were built past Mountain Springs in 1865-70. The residents of San Diego planned, financed by public subscription, and built the roads, as they were the only people vitally interested in San Diego’s commerce with the east. The first automobile road over the barrier was built in 1912-13, entirely financed by residents of San Diego. This is the story of the building of those roads, and the circumstances that led the people of San Diego to rise to the challenge presented to them.
The First Routes from Yuma to San Diego
The mountains to the east of San Diego rise from the Pacific shoreline in gentle stages through well-watered valleys to the summit of the Main Peninsular Mountain Range. At its eastern approach to the desert, the escarpment is reached, “a steep and rocky declivity,2 the jumping off place.”3 There, the terrain plummets precipitously from the rim of the escarpment to the desert down the slope of near solid rock mountains covered with enormous boulders and often choked with thick brush and cactus. For wagons, this barrier was impenetrable with the resources and technology of the 1849-61 period, so the tide of commerce swept to the northeast of San Diego.
The earliest trails circumvented the barrier between Yuma and San Diego by following northwesterly trending valleys that led in relatively easy stages to the Los Angeles area. The best known of these natural routes, later to be known as the Southern Emigrant Trail, was pioneered by the small horseback army of General Stephen W. Kearny in 1846 and further developed by the Mormon Battalion traveling behind Kearny in wagons in 1846-47. During the US-Mexican War of 1846-48, both of these small armies came from New Mexico to occupy California for the United States. The trail ran westward from Yuma, dipping into Mexico to go around the sand dunes, past the sites of the future towns of Calexico and Plaster City, into the “Carrizo Corridor,” past Vallecito, Warner’s Pass and Ranch, then on to Los Angeles. The famous Butterfield Overland Stage used the trail from 1858 to 1861. The route to San Diego was a side trip southwest from the Southern Emigrant Trail across the grain of the mountains. Kearny’s army went south from Warner’s Ranch to Santa Isabel, then to San Pasqual and Mule Hill, where battles with the Mexicans were fought, then on to San Diego.
The Mormon Battalion, with their wagons following behind Kearny as an army of occupation, continued past Warner’s to Temecula, then followed an existing wagon road to San Diego. Today, the most prominent side route across the mountains is the one now commonly referred to as the “Jackass Mail”4 trail, which left the Emigrant Trail near the mouth of Box Canyon to go over the barrier on mule-back on a narrow foot trail that led to Cuyamaca. Wagons then carried passengers and mail to San Diego.
These roads or trails, however, were at best 50 or more miles longer than the more direct route past Mountain Springs. The Mountain Springs route was unknown to all but local Indians until 1851.
The Discovery of Jacumba Pass
The first known pioneer of the Jacumba Pass route was Captain Nathaniel Lyon, quartermaster of the US Army post in San Diego in 1851.5 He was looking for a more direct route than the Mormon Battalion Road from San Diego to Fort Yuma. He set out due east from San Diego and found his way to a kind of basin, or large valley surrounded by mountains, called by Indians living in it “Jacum.” An Indian from Jacum guided him along a very steep Indian trail directly down from the summit of the mountain ridge to Mountain Springs, then down Devil’s Canyon to the desert. Captain Lyon claimed his route “shortens the present wagon road about 80 miles, and with a small amount of manual labor can be made an easy route for pack mules; wagon route cannot be obtained short of much labor previously bestowed.”6
Five weeks after the above report, the San Diego Herald reported that 6,000 sheep driven by a party of Mexicans from Yuma “are coming by the new route recently discovered by Capt. Lyon, U.S.A., and will pass by this place, on their way to Los Angeles.”7 Over the next five years, there were several reports of very large flocks traveling this route.8 The rock corrals, whose ruins can still be seen to the west of Interstate 8 at Mountain Springs, were built by the sheepherders at that time.9
General Williston’s Wagon Road
The first documented traveler over the Mountain Springs grade with wheeled vehicles was Lieutenant E.B. Williston. The San Diego Tribune, citing an interview in 1916 with then-aged General Williston, reported that he “believes he was the first white man to break a trail to Yuma with wagons, if not the first under any conditions.”10 In or shortly after 1856, Williston was a lieutenant in the light artillery stationed in San Diego when he was ordered to take a battery of artillery, including six-horse teams and wagons, to Yuma. For reasons not stated in the article, he did not take one of the existing wagon roads over to the Emigrant Trail. Instead he followed a route through the South Bay, crossing the border into Mexico, back into the U.S. through Campo to “Jacumba Canyon, Coyote Well, Indian Well, and from there by the old trail to Yuma.” He states, “In covering that part of the trip between Jacumba and Mountain Springs we encountered the worst grades in our experience, and in addition to locking the wheels we cut down oak trees and dragged them behind the wagons.” Williston’s unit stayed in Yuma several months, then returned to San Diego. The article does not state by which route or with what equipment they returned. Inspection of the route makes it appear unlikely he returned up the grade with wagons.
San Diego did not have a newspaper from 1860, when the Herald stopped publication, to October 1868, when The San Diego Union began publication of a Weekly. The first wagon road past Mountain Springs was built during this period,11 and the circumstances and dates of construction are unknown.12 The first documented and dated proof of the actual existence of a road past Mountain Springs is found in a petition for a school district for Milquatay (Campo) dated January 26, 1867. The eastern boundary of the school district was defined as being at “Coyote Wells on the newly opened road from San Diego to Fort Yuma and known as the Jacumba Route.”13 So far as known, the circumstances of the building of this road are lost to history. However, its route over the mountain to Mountain Springs and along Devil’s Canyon is known, and the mountain portion can be traveled by high clearance, four-wheel drive vehicles today.
Above Mountain Springs, the road climbed over 800 feet in elevation in less than a mile, an average grade of 18.3 percent, with sections of over 30 percent grade.14 Below Mountain Springs, the road went along the bottom of Devil’s Canyon to the desert near current Ocotillo on Interstate 8. Settlers mostly from Texas used the new road in 1868-69 to settle the Milquatay Valley (later called Texas Camp, and now Campo). Using the new route, Milquatay was only about 50 miles from the Mormon Battalion Road at a point near today’s Plaster City, but 240 miles by the roundabout route along the Mormon Battalion Road to San Diego, then back east along the Mexican border to Campo.
Several well-known pioneer families left accounts of travel up Devil’s Canyon and the steep mountain grade sometime in 1868-69 in wagons that were “double- teamed,” pulled by 12-oxen teams, up the mountain.15
The Stagecoach Road
After the Central Pacific Transcontinental Railroad was completed in 1869, there was a boom in travel between Fort Yuma and the Eastern States via San Francisco. The Indian Wars in Arizona were in progress, and the military based in Fort Yuma created much traffic in passengers and supplies. Before 1868, this traffic traveled by steamboat via the Isthmus of Panama route. Ocean steamers brought them from Panama to the north end of the Gulf of California (Sea of Cortez), where they were transferred to river steamers for the 135-mile run up the Colorado River to Fort Yuma. After the transcontinental railroad opened in 1869, passengers and supplies from the East came by rail to the San Francisco Bay. From San Francisco, there were two possible routes to Fort Yuma: (1) by steamship around the tip of Baja California, then up the Sea of Cortez to the mouth of the Colorado River, then by river steamer to Fort Yuma; (2) by steamship to San Pedro, then stagecoach or wagon to Fort Yuma over an established wagon road. A third option, by steamship to San Diego, then over the Jacumba Pass road to Fort Yuma, would be a week faster than the all-steamer route and three days faster than the San Pedro route. But this option was not practicable because of the difficulties with the existing Jacumba Pass road.
There was a popular movement by the citizens and the business community of San Diego to improve the Jacumba Pass road and establish stagecoach and freight lines over the Pass to Yuma. The San Diego Union, which started publication in October 1868, became the enthusiastic booster and cheerleader of this effort. Two prominent local entrepreneurs made what appear to have been serious attempts to “stage the line.” The first known attempt was by “M.M. Price, Esq.”16 who, according to the newspaper, would by November 4 start to “run a line of stages between this place and Fort Yuma.”17 After much announcement and two more Union articles,18 Mr. Price’s plan to operate a stage line disappeared from the pages of the Union without explanation, never to be mentioned again. Approximately a month later, on November 21, 1868, the Union,19 stated that “Day begins to dawn, at last, upon our Fort Yuma road” because Seeley and Co. were purchasing stock and equipment “with which they intend to stage the line.”20 After this optimistic article, Seeley’s stage line to Yuma also disappears from the newspaper. The Union was apparently in the business of promoting a stage line, not dwelling on the difficulties of doing it.
In the late nineteenth century, the federal government indirectly encouraged the building of roads by awarding contracts for carrying mail between certain cities along defined routes. If the winning mail contractor needed a new road to fulfill his contract, it was his responsibility to get it built. The contractor was expected to help cities along his line by carrying passengers and light freight, in addition to mail. A road suitable for a small, light buckboard21 might not accommodate a tall, heavy stagecoach designed to carry passengers and freight. If a city was particularly interested, it could help the mail contractor in building a road suitable for a stagecoach that he alone might not be able to afford.22
J.C. Capron of Tucson, Arizona, received the contract to carry the mail between Los Angles and Tucson via San Diego sometime in late 1868.23 The San Diego Union reported on January 2, 1869: “J. C. Capron, Esq., of Tucson, the mail contractor for this route, is in the City.”24 The contract value to Capron was $84,000 per annum (about $1.5 million in 2015).25 On the San Diego to Yuma segment, mail was carried by buckboard. Sometimes it went via the Jacumba Pass, at other times by a route below the border with Mexico.26 Capron took up residence in San Diego to work on solving the manifest problems with the Jacumba Pass Road and establishing a heavy stage line.
A week after Capron’s arrival in San Diego, a public meeting was held on how to improve the road to Yuma.27 Capron stated that the principal difficulty was “a rough steep hill, which needs to be graded around.” This is the first direct mention in the Union of the problem. A road committee was appointed and about $2000 in pledges for road improvement was obtained. About ten days later, the Union reported “Sixteen men are now busily engaged upon the Fort Yuma road . . . and they intend to have it in perfect condition for the spring trade.”28
From February through May 1869, there were ten articles in the Union about road construction, mail lines, and related matters. In April, the Union reported “our streets were filled with teams, recently arrived, for the purpose of conveying freight from this place to Fort Yuma.”29 On June 2, 1869, the Union carried an advertisement by Capron stating, “A Weekly Line of Four-Horse coaches will commence running between San Diego and Fort Yuma on and after Wed. next.”30 A week later, an article in the Union stated, “The good day has come at last. Fort Yuma, the hottest place in America, is connected with San Diego, the best climate on the continent.”31 Two months later, the newspaper announced, “The stages from here to Fort Yuma are running full.” According to the Union “Every old croaker in the county” had predicted that Capron’s line would fail, but it had paid from the start.32 Capron’s improved road down the mountain and through the canyon to the desert appeared to be a success.
The New Turnpike Road
Although the newspaper reports sounded cheerful about the Yuma stage line, something was plaguing the operation. Capron had left for the East in early November 1869, where he was married. When he returned to San Diego with his bride about January 19, 1870, he found his stagecoach operation in crisis.33 About two days after his return, there was an emergency meeting for the formation of a joint stock company to build a toll road. The Union reported “…our road to Fort Yuma…we must do something now, to meet the present emergency.”34 This meeting was attended by city leaders including Alonzo Horton, Judge Swift, and Supervisor G.W. McDonald. A committee of five was appointed “to mature a plan of action” to be presented at a future meeting, held three days later. A resolution “in favor of the county giving a franchise to a joint stock company to build the road” was adopted. Civil Engineer C.J. Fox, Capron, and a railroad engineer gave estimates ranging from $20,000 to $30,000 for the cost of building the road.
Road building plans continued over the next several months. A meeting of the “San Diego and Fort Yuma Turnpike Road Company” was held in March 1870. The Company organized with a capital stock of $50,000; share price was $25 each. The newspaper reported that Fox “was appointed to make a survey of the road and report at the next meeting as to grades, cost of work, etc.”35 Three weeks later, the engineer had completed his survey and gave his report.36 The Devil’s Canyon road would be completely rebuilt, including two new bypasses along the canyon walls, one 500-feet and one 700-feet long, with maximum grades to be 12 percent. The mountain road would be abandoned, and a new road would be built. The average grade would be 12 percent with a maximum of about 15-16 percent. Gpc estimated the cost as $3,000 for the Canyon and $3,000 to $4,000 for the mountain. Fox’s report was accepted, and a superintendent of roadwork was appointed. Company officers were elected, with Capron one of the directors. Within five days, work on the road began.
No more newspaper articles appeared on the progress of the road building. About six months later, however, there is a letter giving a traveler’s report of a trip over the new road by stage, starting at San Diego on October 1, 1870.37 The route was through Milquatay, Jacumba, and down the new road to Mountain Springs, with “Vet” the stage driver. A traveler wrote:
…I took a slight snooze, but was recalled to the world by Vet’s voice, “Now is the time to keep your eyes open if you want to see some good made road.” The moon was just going down and the road before us seemed to strike directly into the mountains: this was the old road. The new road was plainly visible, winding round and round the mountainside, almost beneath us. “That’s our road,” said Vet, pointing at the same time with his whip where the road went wending downward. “Get up,” and the whip snapped, and away we went down the hill, at a good round lively trot, without jolting or jarring, as smoothly as if on a racecourse. We reached Mountain Springs in 20 minutes after we got on the new road; going over in these few minutes, what was formerly a dangerous day’s drive for teams. The only way to appreciate it [the new road] properly was to have traveled over it [the old road] in the past two or three times, and have received about as many upsets.38
This letter reveals what the main problem with the old road had been: it had taken a whole day to make the descent of less than a mile to Mountain Springs with coaches often being “upset.”
Both the old and the new roads are today intact, if somewhat eroded, and plainly visible on aerial and satellite photos. The old road over the mountain to Mountain Springs was abandoned. It ran southward from Mountain Springs to climb to the summit of the mountain with one switchback, gaining 900 feet of elevation in 0.8 miles. The new road went around rather than over the mountain. It ran northward from Mountain Springs, and rounded the shoulder of the mountain to head southwest along the wall of a canyon to intersect the old road beyond the old road summit, reducing elevation gain by 90 feet. The new road made the climb in about 1.7 miles, at an average grade of about 9 percent, nearly constant, with no steep switchbacks or pitches.
On April 13, 1871, the San Diego Union offered a fact-filled account of the first annual meeting of stockholders in the Turnpike Company.39 The first annual report summarized the past year’s effort. Road building had started about March 26, 1870.40 The road from the “Desert to Jacumba Valley” was completed September 5, after 5 months and 10 days work and a cost of $13,691.81. The estimated cost had been $6000 to $7000. The cost overrun was attributed to the “rocky character of the canyon, the great amount of blasting41 required, and (chiefly) the difficulty of disposing of the rock after it was broken.” A tollgate was erected mid-September at the foot of the mountain grade near Mountain Springs. Toll collections were about $180 per month.
Further newspaper references to the roads or stagecoach operations are infrequent and indicate only that Capron purchased new horses and equipment for the line, suggesting that the line was prospering.
On October 24, 1870, twenty-year-old George White Marston arrived in San Diego by steamer from San Francisco. That same day, he got a job as clerk at the Horton House hotel.42 One of his duties was to dust off the travelers who arrived by stage from Yuma, including Major General George Crook who traveled over the stage route in June 1871.43 There is little comment about the trip in Crook’s autobiography, save a note that the first 100 miles from San Diego was very mountainous, and that the desert heat was unbearable.
In 1874, Capron sold his stage line to Kerens and Mitchell whose intention was to extend their line of Concord coaches from El Paso to San Diego. The Union speculated that this would afford “a safe and speedy means of crossing the continent during the season when the Union Pacific is blockaded by snow.”44 Under Kerens and Mitchell, the stage line continued to prosper.45 The mail service was increased in the spring of 1877 from three times per week to daily delivery.46 Traffic over the line was especially heavy in the winter of 1876-77.
The Railroad Comes to Fort Yuma
During the 1870s, the railway from San Francisco was building its way south to Los Angeles and on towards Fort Yuma. The railroad finally reached the west side of the Colorado River near Yuma on May 21, 1877.47 The last article in the Union about passengers departing on the stage for Yuma was on February 10, 1877. Operation of the passenger stage may have ended at that time, though San Diego could have lost its stage traffic earlier. It would have been faster to stage from the still building railroad’s “end of track” to Fort Yuma than to use the San Diego route.48
The last reference to the stage line is an advertisement in the Union on August 23, 1877: “Four-Horse Concord coaches leave Yuma daily immediately after arrival at Yuma of [railroad] cars.”49 Kerens is last mentioned on November 3 as “one of the proprietors of the Southern Overland Mail” who was stopping at the Horton House. There are no further articles about the Fort Yuma stage line after 1877 in The San Diego Union.
Little is known of use of the Jacumba Pass road through Mountain Springs after the railroad closed the stage line. Rather than driving his own rig over the desolate road to the Imperial Valley, or Yuma, a private traveler from San Diego almost certainly would have taken the stage to Los Angeles, then the train to Yuma. Any traffic must have been limited to locals, miners (if any), the occasional excursionist, or the adventurer. By the turn of the century, the old stagecoach road lay largely abandoned and neglected.
The Imperial Valley and the Automobile
The development of the Imperial Valley and the advent of the automobile demanded that Jacumba Pass be used once again. Imperial Valley development began in 1901 when a system of canals brought water about 50 miles from the Colorado River into the Valley to create one of the richest farming areas in the United States. Almost overnight, what had been barren, unoccupied desert was developed into about 1,000 square miles of rich farms and several new towns. The center of the Imperial Valley is about 50 miles west Yuma and about 120 miles from San Diego via the Jacumba Pass.
The automobile and the truck opened the possibility of private and commercial travel in a day or less between San Diego and the Imperial Valley, even with the primitive vehicles of the time. In 1903, San Diego county road supervisor James Jasper and Bryon Naylor, an early auto dealer, drove a single-cylinder Cadillac from San Diego to Jacumba via the Jamul-Campo route in 7 hours and 45 minutes driving time “including all stops for teams.”50 Supervisor Jasper reflected:
When we reached the summit of Jacumba Pass, I paused and I gazed wistfully out over the surrounding country to the east, floating in the fascinating mirage, lay the great Imperial Valley, an empire in itself – “so near and yet so far,” our heritage: lost for want of transportation…An auto road to Imperial would be one of the best investments the people of San Diego could make….The auto is the coming vehicle. In fact, it is already here, and it’s come to stay: best we welcome it, and in the future build our roads with an eye to its requirements.
It was only 50 miles further to Imperial, but the route down the mountain and in Devil’s Canyon was all but impassable. Ed Fletcher traveled the old stage road from Jacumba to the desert in about 1910: “It took us two days. Going down the thirty percent grade into Mountains Springs, we had to jack-up our car a number of times and rebuild sections of the highway to make it passable. This went for Devil’s Canyon, too.”51
Given the growing economic importance of the Imperial Valley, public pressure mounted for a real “auto road” over the Pass. This would result in the building of a new road that abandoned both the mountain and the Devil’s Canyon routes.
The First Automobile Route
Ed Fletcher, after whom Fletcher Hills and Fletcher Parkway and other San Diego places were named, was the guiding spirit behind the movement for the new road. He pulled the ropes, greased the skids, and raised the funds for a new road, on which construction began in late 1911 or early 1912, using Fletcher’s grading machines.
The first automobile route is known as the Boulder Canyon Route. The new road abandoned the mountain route of the old stage road 4 to 5 miles east of Jacumba, then ran eastward over In-Ko-Pa summit (where Interstate 8 currently runs) and along Boulder Creek canyon to Mountain Springs. The road did not run along the canyon bottom, but ran in a “notch” cut in the very rocky canyon walls well above flash flood waters. The road was still under construction but passable in April 1912 when the Union’s “pathfinder” car, a Chalmers 40, used it then passed through Devil’s Canyon to the desert.52 On April 25, an “Automobile Stage,” a seven-passenger six-cylinder Franklin, completed its first round trip from San Diego to El Centro and back. The return trip took 11 hours, 2 minutes, and the “trip was enjoyed by each of the six passengers.”53 Apparently these auto stage “buses” began running as soon as the new road was passable.
The next road to be built was the Myer Canyon Route. After completion of the Boulder Canyon segment, the road over the barrier was serviceable, but the Devil’s Canyon section left much to be desired. The road was rough, tortuous, and slow even in the best of condition. Most of the road was in the canyon bottom, subject to washout or rock slides with every heavy rain and requiring frequent closures and expensive repairs. The decision was made to abandon Devil’s Canyon for a new, all-weather road running along Myer Canyon (also called In-Ko-Pa canyon or gorge). Although the entire road was in Imperial County, it was built by San Diego County and largely, if not completely, funded by San Diego. Imperial County gave enthusiastic support, but their financial contribution was not significant. San Diego’s cost was $70,000.
On April 10, 1913, The San Diego Union reported, “Construction was begun November 3, 1912. Road completed yesterday.”54 This new road did not run along the bottom of the wash, as in Devil’s Canyon, but along the steep walls of the canyon at a relatively constant grade. The roadbed was “dirt,” appearing to be rather coarse decomposed granite. It followed every convexity and concavity in the canyon walls along which it passed. It therefore had almost continuous curves, some of very short radius. A large bridge had to be built across the mouth of Myer Canyon at its entry to the desert. The new road was 6.5 miles in length, with a maximum grade of 7 percent.
A gala opening ceremony was held at Mountain Springs on April 9, 1913. “San Diego and Imperial Valley Celebrating Opening of Highway Cut Along Rocky Canyon’s Sides,” reported the Union, and “Devil’s Canyon exists no more.”55 At the opening, there were 175 cars from San Diego, and 55 from various Valley cities. After the ceremony, the entourage went down to the desert on the new Myer Canyon road, then back to Mountain Springs on the old Devil’s Canyon road. This was done so that the achievement of the new road could be fully appreciated. The Devil’s Canyon route was then officially closed to traffic.
Roads in the 1920s and 1930s
In 1926-27, both the mountain and canyon sections of the 1913 road were paved with concrete 20-feet wide. According to the newspaper, the road was “practically the same climb as it was before paving, except that the dangerous curves have been eliminated.”56 At about the same time, the wooden plank road over the infamous sand dunes west of Yuma was replaced by a paved road: “Dreaded Barrier Converted to Splendid Highway,” reported the Union.57 San Diego was now within six hours of the Colorado River.
The newly paved road, however, had many curves, some of very short radius. This made for slow and dangerous going, both up and down grade, especially for trucks. Many truckers preferred hauling Imperial Valley produce to San Pedro, even though it required an extra 100 miles of desert travel, rather than risk the hazards of the Mountain Springs grade. The cost for hauling cotton to San Pedro was $3.50 per ton compared with $4.00 to San Diego. The Union commented that the problem was “the barrier of the Mountain Springs Grade.”58
In late 1938, the city began the “Mountain Springs grade realignment project.”59 The first construction unit of 255 miles from near the summit down to Mountain Springs was completed by January 1940.60 The new road eliminated all of older road’s sharp curves. It was 30-feet wide while the old road was 20 feet, and the minimum curve radius was 600 feet compared to 128 feet on the old.
The new road stayed lower in Myer Canyon in the upper two miles below Mountain Springs and separated from the old 1926 road by as much as a half mile. The cut-off section of the 1926 road has therefore survived, since it was not obliterated by the new construction. This road is accessible by high clearance vehicles today.
Interstate 8 was built from the 1960s to early 1970s. It has an average grade from Coyote Wells to the In-Ko-Pa summit of 4.2 percent with a maximum of about 7.5 percent just above Mountain Springs. Modern automobiles can maintain the legal 70 mph or higher both up and down grade without slowing. Older cars with marginal cooling or less efficient fuel systems can have problems because of the 11-mile sustained climb and high temperatures. Temperatures at the foot of the grade often top 110 degrees Fahrenheit in the summer, and still be 100 degrees at the summit. To assist drivers with overheating problems, there are 25 pull-outs with radiator water reservoirs on the up-grade side, placed about every half-mile.
Drivers of heavy big rigs manage their speed carefully on the downgrade. A runaway truck ramp is located 5 miles below the summit. The last 3.2 miles before the ramp averages over 6 percent grade. The ramp is located to stop runaway trucks before they enter the narrow and winding Myer Canyon. The truck driver’s challenge continues for about 5 miles in Myer Canyon, where the grade averages 5 percent, there are numerous curves, and sight lines in the twisty canyon are short.
In September 1976, much of the Myer Canyon downgrade washed away in the Hurricane Kathleen flood. Over 10 inches of rain fell in about 6 hours in the Mountain Springs basin and Myer Canyon. The flood that raced down Myer Creek also washed away the bridge over which the westbound lanes of Interstate 8 crossed Myer Creek wash. Interstate 8 was completely closed for 7 days, until a temporary road across Myer Creek wash was built and the former uphill only lanes were converted to two-way traffic. It took about a year to rebuild the downhill lanes and the washed out bridges and to restore full freeway operation.
At this time, almost all traces of the old Devil’s Canyon roads vanished. A popular jeep road ran along the bottom of the Canyon before the flood, but it disappeared and has not been rebuilt.
The summit of Jacumba Pass is one of the windiest places in Southern California. Superheated air rising up from the vast below-sea-level Colorado Desert to the east induces a strong flow of cooler air from the Pacific coastal area near San Diego. The wind whistles eastbound through the peaks of Jacumba Pass, down across the Mountain Springs basin, and down Devil’s and Myer Canyons. The interaction of vehicles and wind speeds produce strong side forces that buffet and can overturn tall vehicles. Several times each year, Interstate 8 is temporarily closed to “high profile” vehicles by the California Highway Patrol and includes most 18-wheelers and motor homes. Wind fences have been built at three locations where the wind problem is at its worst.
Over a period of almost one hundred years, the development of six versions of the road from the summit of Jacumba Pass down the mountain and through the canyons to the desert illustrates San Diego’s commitment to infrastructure and communications. The success of Interstate 8 has been made possible through a remarkable series of engineering innovations that continue until the present time.