More on the 1969 Inland Empire flood

Over the years there have been several floods in the IE. The most famous is the 1969 flood. In 1969, Day creek flooded down Haven ave running over 12 feet deep for the entire length of the highway. And Archibald, up above Hillside was in full flood. The Damn at the head of the canyon broke and all of the mud and debris either flowed down through the Horse Shoe Canyon and down Archibald or joined the raging Cucamonga Creek. In Etiwanda the Deer Creek was over 200 feet wide as it flowed out of the foothills after the damn at the head of Deer Creek Canyon broke, moving south and crossing over and closing Foothill in this area as well and effective isolating Chaffey Jr College. Lytle Creek broke its banks, washed Sierra ave in North Rialto, washed out the tracks coming out of the Cajon Pass and added its flow into the already swollen Santa Ana. On the Desert Side, The Mojave flowed above ground for its entire length out into the desert and formed a lake on the surface over 200 square miles round. Route 66 is Adelanto was washed away in several areas and in the Spruce Box Canyon of highway 138 leading to the Lucerne Valley, almost the entire valley was under water isolating several horse ranches in the valley. In Hesperia several miles of open desert flooded as water poured out of the Mountains after 100 inches of rain fell on that side. On the southern Deserts near Palm Springs and leading down to the Salton Sea all of the dry creek beds suddenly swelled with rain runoff coming out of the mountains. The Anza river flowing out of Box Canyon south of Palm Springs threatened to flood the small communities of La Qunita and Indio. And the White Water Creek broke its banks, and flowed across and down the 10 freeway for over 20 miles, all of the way to Indio. Its waters merged with the Coachella river and several others and flowed south into the Salton Sea rising the Salton Sea by over 4 feet and dooming it to future flooding. Water coming from the southern side of the Joshua Tree National Monument and the Little San Bernardino Mts added to the flow of the Coachella River and destroyed many homes south of Indio as it also flowed south into the Salton Sea. Back in Upland, all of the earthen damn along the base of the Mts broke and the water flowed through the ruined lemon and orange groves from the 1968 December freeze and snow. The word went out to the residents of Upland and Alta Loma for volunteers to build a giant earthen burm to keep the waters out of Upland and Montclair. Over 1200 people responded to the call for help and built the burm which can still be see today from Campus up to Baseline and then east into what is now the Upland Meadows Golf complex and homes. In 1969, that entire area was washed away and flooded for over 2 years before the waters finally evaporated from all of the small lakes and bogs that formed. And then it snowed the last two days of the storms. Almost 4 feet of snow fell down to 5,000 in the Mt's. There were thousands of waterfalls and small streams careening down out of the mountains. At Arrowhead Springs on Highway 18 above San Bernardino, water was flowing freely down the canyon almost 20 feet deep and extended the entire width of Waterman Canyon. In the Cajon Pass, The Cajon Creek washed then old highway 395 as it snaked its way through Blue Cut and Kenwood. Lost Lake was no longer lost as it swelled to nearly 100 times its normal size. It was a bout this time that the decision was made to finalize plans for putting the 15 freeway through but about 500 to 1,000 feet higher to avoid future floods. The water from this area made its way down into the Santa Ana River and eventually Prado Damn. Another Dam that officials were concerned about was San Antonio Dam above Upland. For the first time in its history it was nearly full and the eastern flood gates never before opened, were opened and water and desires flowed down into Montclair and finally down into Prado Dam. Euclid Ave was closed as the waters from the Prado Dam backed up and flooded all of the farmland and cattle country that makes up Chino. Chino women's prison had to be evacuated as waters from dam backed up and flooded all of the southern buildings and the Chino Men's Prison also had to move men out of the rising waters. Corona Airport was closed. Hammer ave was closed before it crossed the Santa Ana River. Archibald was open but it was like driving through a swamp with water up to the street level and water everywhere in the valley between Corona and Norco and the cities to the north. If I missing anything please let me know. I am sure I have missed several areas, but I think I have given you an idea of how bad the valley can flood when a 150 rain comes in and floods ravage the IE. gdh.


The 1938 flood was termed a 100-year flood, and it prompted the County to establish the Flood Control District to implement measures to avert any such disaster in the future. By 1969 there had been massive construction of channels, settling basins, etc. Those measures undoubtedly prevented the '69 flood from reaching 100-year status. During the '70s the SBCFCD had displayed on the walls of their offices at 825 East Third Street two very large aerial mosaic pictures of the valley--one taken just after the '38 flood, and one contemporary mosaic in which the extensive network of constructed facilities was visible.
In San Bernardino the expanse of water created in the '38 flood by the Santa Ana River reached a few blocks north of Mill Street at Arrowhead Avenue. My husband lived in the first block north of Mill, and his family was the last one on the street rescued on wheels. Everyone after them was evacuated by boat.
By comparison, however, the 1862 flood created a continuous body of water from downtown Third Street in Berdoo to the bench north of Pioneer Street in Redlands. That disaster is ranked a 1,000-year flood. The millions of waterworn boulders you see throughout Mentone and the east end of the valley got there during that flood. Engineers performing core drilling for soil samples out there toward Greenspot Road encounter cow bones and fenceposts 40 feet down; before the 1862 flood it was a rich truck-farming area like the Cooley Ranch (W of I-215 & S of I-10).
One thing I've been interested in noting is how the Santa Ana River canyon east of the valley has during recent decades filled up with deciduous trees, leaving a rather narrow water course. As late as the mid-50s the whole width of the canyon was just rocks and sand, apparently having been stripped of trees by the torrential force of the '38 flood.
I knew an old Forest Service employee who had taken a crew of men upriver for some field work the day the Santa Ana went wild in '38, destroying the highway. They had to find their way out of the mountains on foot, along the sides of the canyon, taking several days to get back to the valley.
One result of the '69 flood that not many people even in Yucaipa know about could be described as a freak occurrence. It started in Oak Glen, above the apple orchards, where a the face of a hill had for centuries enroded down the center, depositing soil against a massive boulder. The accumulation of soil eventually enveloped the boulder, leaving a somewhat level area on the uphill side of it. That level area in the lower reaches of the hillside slowed the water draining down its little ravine, producing a sort of natural settling basin. Well, by the day AFTER the '69 flood, a huge area of those lower reaches of that hillside had reached the saturation point. Liquefaction had occurred, but the liquid mud couldn't go any place because that massive boulder was trapping it in its natural underground basin. Then came the decisive moment when the weight of the liquified soil popped that huge boulder out of the ground, opening the floodgates to a river that burst through Bob Bice's apple trees, sending a several-feet-high wall of mud flowing eventually through Wildwood Canyon clear to I-10, permanently changing the terrain on the north side of the freeway opposite the Live Oak Ranch east of Live Oak Canyon Road. That day a number of people had gone to look at Wildwood Canyon to see how much flooding and damage had occurred where several of Yucaipa's streets cross it. Consequently they were standing there surveying the canyon when the spectacle of that wall of mud came marching down the chasm, enveloping buildings halfway up their windows.
I could go on and on, but I did want you to be aware that 1938 and 1862 were the most major floods in recorded history of the valley.
And another thing. Please don't spell dam "damn." If you'd like, I can edit your whole article and email a cleaned-up version of it to you. Your website serves a very good purpose; but like hundreds of other people I've known over the years, including some with multiple doctorates, English class wasn't your finest moment. And many of you have wound up with your written material on the net, trumpeting your lifelong indifference to the finer points of the King's English.

Thank you for so much information on flooding in San Bernardino area. The extent of flooding there was very interesting. There seems to be some question as to the ranking of 1938 as a Hundred Year event. San Bernardino County Flood Control's history lists 3 storms in the 75 years preceding 1938 as bigger floods--1862, 1867, and 1891. That would make 1938 about a 25 Year Storm. The carbon dating of area verve done in the 1990's led those researchers to conclude that storms the same size or even larger than the one in 1862 had occurred around every 120 to 190 years. That conclusion is intimidating given that 1862 was evaluated as 320% the size of 1938 storm.

Looking for all info related to the building of mt. san antonio dam especial the pipe and concrete flood ditch that was built.


Don Hoffman

The Badlands is alive and well!

Hey I know it's still there just need all the historical background. Any help on this would be appreciated.

What specifically are you looking for? I've information beginning with preliminary plans from mid 1930's, including the Lippincott letters and evaluations of the Corps design that precipated the building of the two dam models (proving that the Corps design would fail). Plus the battle between San Bernardino and Los Angeles counties over the concrete ditch. If you are looking for design and construction of the dam that was built, the Corps Design memorandums were in depository libraries. I saw them in either Cal State Fullerton or Cal poly Pomona . The NARA design memos in Riverside which I reviewed have been withheld from viewing by public as a consequence of 9/11. I did not copy entire design memos. They may eventually be available again. The NARA College Park has a lot of documents on the inadequacy of the dam the Corp actually built, including statements and logs of BAE personnel stationed on San Antonio Creek during the much larger 1938 storm.

I don't know if any of you have seen this map or not but I first saw on the wall in a geology class that I had at Chaffey College back in the early '90s. I was fascinated by it so I ordered a copy from the USGS sometime during the '90s. Anyway... about a year ago I discovered that it is now available in PDF format online.

It's called "Flood of January 1969 Near Cucamonga California" and you can access it here:

This one covers the Azusa/Glendora area:

Hi Todd, I'm an Environmental Studies and Urban Planning student in Claremont. These maps are really compelling, thanks for posting the link. Did you happen to see one that shows flooding in Upland/Montclair/Claremont?



No. The only maps that I have seen for this flood were Cucamonga, Azusa/Glendora, and then there were two more further west... I think Ventura or maybe Santa Barabara. Take the URLs that I posted and change the 425 or 424 to 423 and 422 and you can see the others.

By the way, there is an article in the October, 1969 issue of National Geographic magazine entitled "Southern California's Trial by Mud and Water" about the flooding that year. I picked up a copy at the Rancho Cucamonga library (in their friends of the library book store) about 10 years ago pretty cheap.

Singer said the USGS was so short handed after 1969 flooding they did not map all areas. Assuming he was as accurate as usual, you are not likely to find a complete map overview. If you need maps For research I have the San Bernardino county flood control maps for western Rancho Cucamonga, Upland and the LA county maps for Claremont etc. They are 11 by 17 so I' d have to have them specially scanned to post for you. Also have BAE maps for 1938.


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