Runoff from potent storms has been flowing into Lake Casitas nearly nonstop via the Robles diversion canal, pictured here at around 5 p.m on March 14.
A major winter storm initially forecast to bring more rain than the previous week’s storm didn’t quite live up to expectations, but did deliver a healthy amount of rain to the Ojai Valley this week.
The warm, atmospheric river weather system that arrived on March 14 dropped about 3 inches of rain on the valley floor, exactly as forecast. “But what we didn’t get was the expected upslope, higher mountain totals that we typically see,” said Mike Wofford, meteorologist with the National Weather Service in Oxnard.
In the mountains, 3 to 6 inches had been forecast, with rainfall totals as high as 8 inches. But the heavier downpours didn’t materialize due to weaker-than-expected south winds, which cause additional lift when hitting south-facing slopes, generating more rain, Wofford said.
Most areas saw rainfall rates of around 0.50 inches per hour and not the 1 inch per hour rates that had been forecast, and that helped keep local streams and creeks in check, according to Wofford. “We got a lot of rain, but we didn’t get too many issues like we’ve seen,” he said.
Apart from the usual nuisance flooding and numerous rock and mudslides, the Ojai Valley experienced few major problems. SR-33 between Oak View and Casitas Springs was briefly shut down the afternoon of March 14 due to a large slide across all lanes on the Arnaz Grade. The slide was cleared within about an hour.
A weak storm will bring a chance of rain to Ojai on Sunday, March 19, forecasters said. If it does rain, totals will likely come in at between 0.10 and 0.25 inches.
A stronger storm will likely bring rain to the area on Tuesday, March 21, but timing and amounts were still in question. “The next one is still a little mysterious,” Wofford told the Ojai Valley News on March 16. “Probably not quite what we saw with the last one. Maybe 1 to 2 inches for the coast and a little bit more in the mountains.”
But like the storms over the past few weeks, this one will also tap into a fetch of warm, subtropical moisture, according to Wofford. “Right now it’s leaning toward a low-grade atmospheric river storm,” he said. “There is some subtropical moisture pulling that across the Pacific, but it doesn’t seem to be quite as much as what we’ve seen with these other ones.”
Snow levels will probably be lower than previous storms, between 6,000 and 7,000 feet, forecasters said.
Recent storms have benefitted water levels at Lake Casitas, which has risen approximately 42.5 feet since fall 2022 and stood at 58% of capacity on March 16, according to Michael Flood, general manager of Casitas Municipal Water District.
Approximately 800 acre-feet per day has been entering the lake via the Robles diversion facility on the Ventura River, which provides about a third of the lake’s water input.
The quality of water going through Robles has improved recently, as strong storms in January and February flushed from the watershed a good deal of debris and material. “We’re still getting muddy water coming down,” Flood said, “but we’re not getting all that plant debris and ash and heavy duty debris flows that cause us a lot of problems.”
This week’s weaker-than-expected storm caused no damage to the facility, according to Flood. “That facility operates very well on water that’s relatively clean, so we’re really maximizing right now everything we can put in the lake,” he said.
With approximately 2,500 acre-feet a day entering the lake from all sources, “we’re probably going to see 60% in about a week,” Flood said.
The water level in the Ojai groundwater basin has risen over 18 feet since last week and is still rising, according to Jordan Kear of Kear Groundwater.
Depth to water at the key well stood at 68.67 feet, the highest level since 2005. The basin stood at 88% of capacity on March 16, at roughly 74,800 acre-feet, Kear said.
