Sunday, July 22, 2018     Volume: 19, Issue: 20
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Santa Maria Sun / Breaking News


Santa Barbara County braces for massive winter storm

By SPENCER COLE

Emergency responders and planners in Santa Barbara County braced themselves for the worst as the largest storm of the year slowly made landfall beginning on March 20.

That day, a mandatory evacuation order went out for the Thomas, Whittier, and Sherpa fires burn areas. As much as 10 inches of rain was expected to fall throughout the course of the atmospheric river-driven storm, with some in the weather community warning that the rainfall could exceed the original estimations.


AWARE AND PREPARE
Santa Barbara County will continue to update its evacuation map at readysbc.org as the storm progresses. (Pictured, above: The recommended evacuation area of Tepusquet Canyon affected by the Alamo Fire. Below: The mandatory evacuation areas for South County affected by the Whittier and Thomas fires.)
IMAGES COURTESY OF SANTA BARBARA COUNTY

"It is possible that the models are actually underestimating the precipitation potential with this event," UCLA Climatologist Daniel Swain wrote on his blog, WeatherWest on March 19.

Swain explained that the storm had a slow-moving atmospheric river—essentially a "river in the sky" laden with tropical moisture from the equator that moves like a conveyor belt of rain—which could cause problems for much of California's Central and Southern coasts.

"It is worth noting that the majority of major historical flood events in California have been the result of a slow-moving or stalled atmospheric river," he said, adding that it appeared the current storm's speed indicated it could park itself over Santa Barbara County and its various burn-scarred areas for days.

"This is a storm to watch very closely," Swain cautioned, explaining it would "certainly rival—and probably surpass—the Jan. 9 storm in terms of overall precipitation, which resulted in the devastating Montecito debris flow."

He said that "despite the storm's potential, it is not a guarantee that the impacts from it will be as locally devastating (hopefully) as the one that triggered the Montecito mudflows," which were spurred by what Swain described as an "extremely intense, localized downpour."

Swain said the risks during this storm "will extend across a much broader region, and there is a real possibility of major flash flooding and large debris flows/mudslides (not just minor stream flooding and muddy streets)."

On March 20, Santa Barbara County officials at the Board of Supervisors' regular meeting acknowledged the threats from the coming deluge and the need for residents to follow evacuation orders.

"The thresholds are clearly being met that require this evacuation," said Robert Lewin, director of the county's office of emergency management. Lewin told the supervisors that his office, the county fire department, law enforcement, and public works department were all prepared for the imminent flooding and accompanying limited road access. "But the objective here is for those resources to not have to be used [unless needed]," he said. "When people stay and don't abide by an evacuation, it puts our people at risk."

Supervisor Das Williams said that he understood how some residents could be exhausted or upset by the seemingly steady stream of evacuation orders issued by the county since the devastating January storm.

"This will be the fifth or sixth time my family has [evacuated] in the last couple of months, so I feel that out there, but I feel very strongly this is not something people should be leaving [to] luck," he said.

Lewin said the storm wasn't a threat to just the Thomas Fire burn areas.

"It's also about the Sherpa and Whittier burn areas, west of Goleta and also the Alamo burn area," he said, adding that while the location of the Alamo Fire was not under a mandatory order that people there needed to be aware of the dangers.

"Those folks in Tepusquet Canyon need to understand their situation," Lewin said at the meeting. "The ground there isn't as steep and the vegetation wasn't as volatile, and there's not as much as the thick chaparral here on the South Coast, but it still has the potential for problems."

Just a half inch of rainfall over the course of an hour can trigger a debris flow or a mudslide. And sometimes smaller amounts of precipitation can still cause slides and flows in areas where the ground has suffered extremely high temperatures from severe burns during wildfires. The storm that arrived Tuesday night was projected to dump at least a half inch in multiple locations, with some areas forecasted to receive as much as an inch an hour.

Swain and the National Weather Service said the initial rain totals would likely be relatively low but that the storm would increase in intensity as made it landfall.

"You've got a combination of steep slopes, high-fire frequency, and lots of people," Jason Kean, a research hydrologist for the U.S. Geological Survey, told the Sun before the Jan. 9 rain event. "That's why Southern California has these problems a lot."

Lewin said the most important thing the public could do was to be aware of current evacuation orders and to obey them if and when they came.

"We are ready and we want the public now to heed this evacuation," he said. "This is not the time to mess around. This is the time to get out of the way."




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