Weather expert explains erratic conditions for Santa Cruz County
Fires could be rooted in past, a National Weather Service meteorologist says
SANTA CRUZ >> Santa Cruz and the greater Bay Area have been the spectacles of powerful and polar weather events in recent months.
While California is no stranger to extreme weather, between droughts and floods, it is unusual to see such erratic weather compressed into a relatively short time. Brian Garcia, a meteorologist for the National Weather Service, Bay Area, said he doesn’t think he’s seen weather such as this throughout his more than 11 years as a California meteorologist.
“It just seems like it’s been all over the map in the last several months,” Garcia said. “Trying to keep on top of it all constantly is a daunting feat.”
Large waves started to pound the coast in early December. The high surf proved to be a problem to people throughout the county. Several people have been swept into the ocean this year, and a junior sailing class experienced a troubling day on the water at the mouth of the Santa Cruz Harbor on Jan. 10.
The waves are the result of this being a La Niña year, according to Garcia. In a La Niña year, the North Pacific becomes very active with storms, which creates a lot of ocean activity. Sometimes that activity passes the contiguous United States and head toward Hawai’i, in other cases, it hits landfall sooner in California, he said.
Typically, the swell brings storms with it, but this year the California coast got the benefit of the big swells and got to enjoy nice weather.
Warm weather and sunshine graced the greater Bay Area, as the beaches packed with people and residents went for walks in shorts and t-shirts, last week. Temperatures in the area averaged in the 70s with clear skies, which is unseasonably warm for January, which is about 10 degrees to 15 degrees warmer than normal.
“We were sitting under a bubble of high pressure,” Garcia said. “That gave us warm days.”
Then came the wind. In La Niña years, a lowpressure jet stream sweeps
the north Pacific. This is what causes the storms in the north and the swells along the coast. Usually, the jet stream hits the Pacific Northwest and creates storms there.
However, that jet stream dived south and collided with the warm, high-pressure bubble that was sitting over the Bay Area. The collision of different temperatures and pressures create extreme weather events.
“When we set up that pressure differential, that’s
when we get strong winds,” Garcia said. “That pattern we typically don’t see this time of year.”
Violent winds across the county resulted in several downed trees, power lines and wildfires, which forced approximately 120 homes to be evacuated in the Boulder Creek, Aptos Hills and Watsonville areas and left nearly 24,000 residents without power across the county.
The issue of having fires in January can be linked to the nearly 8-year drought California experienced within the last decade, according to Garcia. Trees in the area became dried out as a result of the drought. Although California isn’t in a drought emergency anymore, the trees still take time to rehydrate.
“It kind of set the stage for long-term impact in our vegetation,” Garcia said. “It set things up to be a tinder box across the state.”
While the state isn’t in a drought emergency, parts of California are experiencing bad drought conditions. The Monterey Bay is one of the better areas of the state right now and is only classified as a moderate drought by the U.S. Drought Monitor. However, the Bay Area is in a severe drought and parts of Northern California are
in an extreme drought.
“This is definitely a canary in a coal mine type of moment,” Garcia said.
Additionally, bark beetles can cause high mortality rates in trees. While researchers have said that beetle killed trees aren’t more likely to start wildfires, they have recognized those trees burn quicker than healthy trees once they ignite, which can cause a fire to spread.
Weather conditions are expected to continue to change as the county is expected to get rainfall most of next week, starting with the rainstorms seen Friday.
A weather change such as that could offer relief for firefighters in the area who have been working to contain the multiple fires within the county.
“With the predicted rain, that’s always a blessing,” Cal Fire CZU Unit Chief Ian Larkin told the Sentinel on Thursday.
However, that doesn’t mean that the area is clear from disaster. After intense fires, heavy rains pose a serious debris flow risk in the Santa Cruz Mountains.
“There is significant concern (and) potential for debris flow near these burn scars,” said Daniel Swain, a
climate scientist at UCLA. “A lot of it burned intensely, which not only removed the vegetation but resulted in a hydrophobic layer in the soil.”
When the soil becomes hydrophobic, it can’t absorb rainfall as efficiently. So, when there is a lot of heavy rain, it can cause slurries of dirt, rocks, mud and water to move, also known as a debris flow.
“Pretty dramatic shift from just a week ago,” he said.
The substantial change in weather is something that Swain likes to call “precipitation whiplash.”
That is when weather swings rapidly between very wet conditions and very dry conditions, he said. While that is something California sees often with its history of floods and droughts, the whiplash the state experiences are getting worse.
“What we are seeing is that’s actually increasing to a greater degree. We’re seeing hotter dryer summers,” Swain said. “The winter itself is not necessarily drying as much. Within the winter, were seeing more dry days overall, but more intense precipitation when that rain does fall. Short but sharper shock essentially.”
The very dry summer and autumn, followed by the dry winter and potential for heavy rainstorms are prime examples of precipitation whiplash, according to Swain. Researchers expect to see more of these whiplashes as the climate warms.
In fact, a lot of the weather Santa Cruz saw in such a short period of time could be indicators of climate change, according to the Weather Service’s Garcia. The drought and all of the impacts that resulted from it are markers of climate change. He even pointed to recent weather as an indicator of the changing climate.
“These types of wild weather swings, that in and of itself is a thumbprint,” Garcia said.