Weather in the Foothills

“Seems it never rains in Southern California…”

~Albert Hammond

Anyone who was around last winter knows that the song got it wrong: It does indeed rain in Southern California. Southern California’s monsoon and thunderstorm season unofficially began Monday/Tuesday of this week. Just the day before, remnants of June Gloom lingered on. Sometime in the still of the night the stubborn marine layer was beaten back and pushed out to sea; moving in to take its place were cumulus and nimbus (thunderhead) clouds. Welcome, summer weather!

I was awaked by the sound of large raindrops falling in the pool. The brief rain shower was courtesy of a North American monsoon. Precipitation is rare in our area as usually showers remain out toward the desert, over the mountains and farther to the east in Riverside and San Bernardino counties. At the very least, these monsoonal conditions bring a sticky, tropical feel to the Crescenta Valley, making our hot semi-desert climate uncharacteristically muggy. But occasionally, showers and thunderstorms spill over into the northern reaches of Los Angeles Basin. Here’s a simple explanation of monsoon dynamics.

During the summer, tropical moisture from the Gulf of California and Mexico flow into the southwest. The moisture-laden air is lifted high in the atmosphere by the rising hot air over the desert regions of the southwest. This lift creates towering cloud formations –cumulus nimbus – and thunderstorms making rain and lightning likely over mountains and desert. A spectacular light show and cooling rain can easily shift to fire ignition and flash floods. Mother Nature’s wrath is not discerning in her ways.

In the midst of such a storm, we traveled to Cherry Valley in Riverside County. Why? “There’s a new pup in town!” Brighton is her name; she’s a 1-year old English Cream Golden Retriever. She was no longer wanted; she adopted us!

Sue Kilpatrick is a Crescenta Valley
resident and  Official Skywarn
Spotter for the National Weather Service. Reach her at