Here's a Dr George Fishbeck weather video from the KABC-TV 7 newscast of the day before the San Jacinto levy had the disastrous break and flood of Feb 1980.
"February 1980 rainfall (following excess rain in January) was record breaking in many (Riverside) County areas. Eleven stations with 50 or more years of record accumulated their highest February totals in history. (San Jacinto) Valley stations were approximately 360 to 430% of normal, mountains and foothills 400 to 510% of normal and deserts 590 to 820% of normal. The (Riverside County Flood Control) District had in place a substantial system of flood control facilities which were severely tested during the 1980 floods...
" Also on February 21, 1980, a section of the San Jacinto River Levee immediately downstream of the junction with Bautista Creek Channel collapsed. An estimated flow of 25,000 cubic feet per second had undermined the rock toe revetment and coursed its way through a mobile home park and portions of the City of San Jacinto, with floodwaters several feet deep and causing extensive damage. Other than these two levee failures, the District's facilities performed well and prevented millions of dollars in damages. The City of Riverside saw none of the damages and flooding experienced in 1969, due to protection the completed 1970 bond issue projects and other projects had provided. However, the floods of 1980 also demonstrated a need for additional flood control and drainage improvements throughout the District, where the widespread flooding in western Riverside county accounted for at least ten deaths, and in excess of $70 million in property damage. " - Pictures of this and other local flooding at: