Was SLO County storm a drought buster? Here’s how weather affected rain totals, lake levels

The Pineapple Express is a subset of an atmospheric river event that originates in the tropical waters near Hawaii — hence the pineapples.

Meteorologists simply referred to these as “the hose” and for a good reason. The time-lapse radar presentation from Jan. 27 and 28 looked like somebody was holding a water hose somewhere far out over the Pacific Ocean and washing down Central California with a stream of fluid aimed mostly at Cambria.

The atmospheric river stalled over Cambria and retrograded northward toward Big Sur, before moving southward into southern San Luis Obispo county and northern Santa Barbara County.

Dawn Dunlap lives above Cambria on the Walter Ranch at 1,250 feet of elevation in the Santa Lucia mountains. She told me that this past storm produced more than 17 inches of rain over the course of 54 hours.

The March 1995 atmospheric river created the same amount of rain, but over 30 hours.

Typically, Dunlap receives about twice as much rain as Cambria due to orographic enhancement, which happens when larger amounts of rain or snow develop on the mountains’ windward side. Like squeezing a wet sponge, moisture from this air mass is released in the form of precipitation.

However, she did not experience the gale-force southerly winds that slammed into Cambria or the reported 90-mph gust that hit Hearst Castle — just a moderate breeze.

Cambria recorded about 70% as much rain as the Walter Ranch.

So far in this rain season, which runs July 1, 2020, through June 30, 2021, Cambria has recorded 14 inches of rain, or, 128% of normal rainfall.

Typically the wettest place in San Luis Obispo County, Rocky Butte reported 18 inches of rain but is only at 90% of average precipitation.

Areas of flooding were reported throughout the Central Coast of California, but nothing compared to the flooding seen in March 1995.

Back in 1995, the ground was terribly saturated before that storm hit. This time, “The hills around our ranch looked more like the end of September than the end of January. They have been bone-dry,” Dunlap told me.

Much of the rain fell to Earth in a delicate matter at her ranch, which allowed the parched ground to absorb much of it.

How much rain fell on the Central Coast?

Was this storm a drought buster? Probably not, but it sure did help.

We are now past the halfway point of this rain season’s heaviest precipitation likelihood.

So far, the Paso Robles Municipal Airport has recorded 6 inches of rain. By now, it has typically received 7 inches.

This rain season, San Luis Obispo County Regional Airport is at 8 inches, while Cal Poly has received more than 15 inches. On average, San Luis Obispo should have received about a foot of the wet stuff at this point.

Farther south, the Santa Maria Airport has reported about 6 inches of rain, but much like Paso Robles, it should be at 7 inches by now. The Santa Ynez Airport has also seen 6 inches but should be at 11 inches by the start of February.

Arroyo Grande, Oceano and Nipomo are all about 80% of average.

How close are local lakes to capacity?

Due to the dry Earth, many of the lakes and reservoir levels did not increase as much as hoped.

Nacimiento Lake had the most significant rise. It went from 21% of capacity to 39% during this past storm, while Lake San Antonio increased to 19% of capacity from 16%.

According to SLOCountyWater.org and the Santa Barbara County Public Works Department, here are the other local lake and reservoir capacity figures.

Lopez Lake is at 40% of capacity, Salinas Reservoir near Santa Margarita is at 73% and Whale Rock Reservoir near Cayucos is at 78%.

In Santa Barbara County, Cachuma Reservoir is at 64% of capacity, and Gibraltar Reservoir is at 13%.

After a low-pressure system produces rain on Tuesday, it looks like a long dry spell in the heart of our rainfall season.

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