Floodwaters and Mudslides Swept Through Portions of Southern California

Following Kay, a lot of rain causes mudslides in Southern California. The effects of Tropical Storm Kay persisted after it passed on Saturday. The system's residual moisture combined with the high temperatures to produce amazing sights like this debris flow.

Flooding and Mudslides

Following Tropical Storm Kay, floodwaters and mudslides raced over sections of Southern California on Monday, prompting an emergency evacuation order for the Inland Empire.

Throughout San Bernardino County, including Oak Glen, flash flood warnings were issued on Monday due to the previous night's heavy rainfall. One Twitter user recorded footage of a massive flow of flash flood debris unexpectedly engulfing a neighborhood street.

Dr. Roger Seheult shared a video with the caption, "If I had been 2 min[utes] sooner... In a subsequent tweet, he clarified that the debris came from the El Dorado wildfire burn scars, which had scorched around 22,000 acres in the Yucaipa region in the fall of 2020. Investigators concluded that a pyrotechnic device used at a gender reveal celebration caused the fire to start.

An expanded version of Seheult's first video shows a guy rapidly turning and running for safety after witnessing another round of debris charge down the road.

Messy Situation

The sound of the rising rubble muffles what he seems to be shouting, "Get out of here!"

On Monday, the Yucaipa Police issued evacuation orders for several areas, including Oak Glen.

Intense gusts and torrential rains were released by Tropical Storm Kay, which was ultimately reduced to a tropical rainstorm on Saturday.

Thunderstorms were able to form because of moisture and residual energy from the earlier Kay, according to AccuWeather Senior Meteorologist Dave Houk. "The residual tropical moisture drove the strong downpours."

Partial Cooling

Although Kay brought some respite from Southern California's extended heat wave, "cooler" temperatures meant the temperature fell below 90 degrees.

Until Saturday, when temperatures dipped to the mid-80s, San Bernardino, the county seat of San Bernardino, was experiencing a heat wave. AccuWeather data shows temperatures have stayed in the 80s since the heat wave surged into the 90s on Sunday.

Following the extra rain, temperatures in Oak Glen have decreased a little more, with the peak temperature from Friday falling by about 10 degrees on Saturday as Kay's downpour closed in on the region. Over the weekend, though, the temperature marginally increased.

Although not everyone could see the storms, Houk stated that they could produce rainfall rates of up to 2 inches per hour where they impacted.

Along with the unexpected debris flow in Oak Glen, the sudden downpour also caused several mudslides that slid down mountain slopes and closed up sections of interstate.

According to Houk, Tuesday will be the final day the pattern will persist in the region. After that, deeper moisture will be pushed eastward through the rest of the week as winds above from the west bring in dry air.

Weather Forecast

After the first week of this month was extremely hot, "the jet stream lowering southward and onshore flow at the surface will also keep daytime temperatures below average." The Inland Empire may have a few hours of low clouds and patchy fog late each night and early each morning, but the more pervasive night and morning clouds will return closer to the coast.

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