Fire, then flood

In new era of dis­as­ters, Cal­i­for­ni­ans wait for next de­bris flow to strike

The Hazleton Standard-Speaker - - ETC. - BY TONY BIZJAK THE SACRA­MENTO BEE

SACRA­MENTO, Calif. — Brent Lar­son awoke at 4 a.m. to the shake and rum­ble of what felt like a freight train rolling down the hill to­ward his Santa Bar­bara County home.

He leaped from his bed and woke his two sons. In sec­onds, a wall of wa­ter, mud and rock slammed into his house, smash­ing through one win­dow, then the next, then a third, pour­ing in as the trio sprinted to the safety of the chim­ney at the home’s far cor­ner.

“It was like out of ‘In­di­ana Jones,’” he said, nine months later, still shaken.

He was lucky. Twenty-one of his Mon­tecito neigh­bors were killed that Jan. 9 night, and 400 homes dam­aged or de­stroyed. Two other peo­ple are miss­ing, be­lieved to be en­tombed some­where in the now-hard­ened mud that still cov­ers parts of Mon­tecito, an up­scale vil­lage next to Santa Bar­bara.

Worse, that night was not a freak in­ci­dent, state emer­gency of­fi­cials say.

Cal­i­for­nia is en­ter­ing what ex­perts call the “fire-flood” era: a for­mi­da­ble one-two punch prompted by warmer tem­per­a­tures, big­ger wild­land fires and more in­tense win­ter rain dumps, even in drought years.

Fall fire sea­son sets the ta­ble by de­nud­ing mil­lions of acres of hill­sides and bak­ing the soil sur­face so that it be­comes non-ab­sorbent, or, in sci­en­tific terms, hy­dropho­bic. When heavy win­ter rains hit, the wa­ter can­not pen­e­trate the burned soil, and in­stead rolls down­hill in the form of a mud and ash soup, sim­i­lar to a flash flood, car­ry­ing boul­ders and trees with it.

“We know where things are headed,” cli­mate sci­en­tist Daniel Swain of UCLA said. “We are just en­ter­ing this era, and it is only go­ing to get more in­ter­est­ing from here.”

As wit­nessed in Mon­tecito, de­bris flows can run for miles, bury­ing high­ways, rip­ping up gas lines, de­stroy­ing homes and tak­ing hu­man life. A quar­ter-mile of High­way 101 was buried in 12 feet of mud soup that morn­ing. Bat­tered cars and trucks ended up dumped on the beach be­low town.

Cal­i­for­nia’s wild­land fires were mas­sive and de­struc­tive again this sum­mer. Mem­bers of the Wa­ter­shed Emer­gency Re­sponse Team from the state De­part­ment of Forestry and Fire Pro­tec­tion have been busy scour­ing fire-scarred hill­sides across the state in re­cent weeks and iden­ti­fied ar­eas ripe for fire-flood de­bris flows should heavy rains hit.

That in­cludes ar­eas on the west­ern edge of Red­ding and around re­mote Whiskey­town where the Carr Fire burned in July and Au­gust, as well as charred moun­tain slopes above In­ter­state 5 north of Red­ding.

De­bris flow con­di­tions can last sev­eral years af­ter a fire. Mon­tecito and other Santa Bar­bara County com­mu­ni­ties re­main at risk, as do ar­eas around Santa Rosa and Napa, where de­struc­tive fires hit in 2017.

A de­bris flow in Oc­to­ber dur­ing a cloud­burst at the Fer­gu­son Fire site near Yosemite forced clo­sure of High­way 140, block­ing peo­ple from get­ting in and out of the na­tional park.

In South­ern Cal­i­for­nia, where more peo­ple live in steep canyons, the risk is more acute, of­fi­cials say.

River­side County has is­sued warn­ings to res­i­dents of Trabuco Canyon about de­bris flow po­ten­tial from the Holy Fire. The state Of­fice of Emer­gency Ser­vices, Cal Fire and oth­ers have sent crews there to do prep work.

‘Flood on steroids’

The “fire-flood” de­bris flow phe­nom­e­non is not new. Hy­drol­o­gists, ge­ol­o­gists and oth­ers in gov­ern­ment and academia have stud­ied post-fire flash floods for decades and know how fast and deadly they can be. One in 2003 killed 14 peo­ple at a church camp in San Bernardino.

De­bris flows are some­times de­scribed as mud­slides, but the two are not the same. Mud­slides oc­cur when a hill be­comes sat­u­rated and large amounts of sub­soil slump and slide. De­bris flows take only the top layer of soil with them, and run more like flash floods, mov­ing fast and sweep­ing up de­bris.

“A de­bris flow is a flood on steroids,” said Ja­son Kean, a U.S. Ge­o­log­i­cal Sur­vey re­search hy­drol­o­gist. “You add rocks, boul­ders and other ob­jects. That weight, it is lethal. You can’t block it with a sand­bag. You can’t out­run a de­bris flow. You need to get out of the way.”

The Jan­uary flood storm in Mon­tecito — home to Oprah Win­frey, Ellen De­Generes, Rob Lowe and other celebri­ties — of­fered a lab­o­ra­tory-like les­son for emer­gency op­er­a­tions of­fi­cials around the west­ern United States.

A somber Win­frey posted a video the next morn­ing of her yard cov­ered an­kle deep in mud. She was lucky. Her neigh­bor wasn’t. “The house in back ... is ... gone,” she said.

It started in early De­cem­ber with the Thomas Fire, then the big­gest wild­fire in state his­tory, which burned for more than a month, prompt­ing more than 100,000 evac­u­a­tions and de­stroy­ing 1,000 build­ings along miles of coastal moun­tains.

As emo­tion­ally ex­hausted res­i­dents re­turned to their homes post­fire, county and state of­fi­cials were meet­ing in war rooms with their eyes on up­com­ing Jan­uary storms. In De­cem­ber, county crews cleared out drainage basins to ready them for the flash floods.

Thirty hours be­fore the rain­storm hit, Santa Bar­bara emer­gency op­er­a­tions of­fi­cials is­sued an evac­u­a­tion no­tice to hill­side res­i­dents.

County emer­gency man­age­ment di­rec­tor Rob Lewin said his team sus­pected the de­bris flows would fol­low creeks and wa­ter­sheds, but didn’t know how far they would spread. So they drew a line across the hill in the mid­dle of town along East Val­ley Road. Up­hill from that line, evac­u­a­tions were manda­tory. Down­hill, they is­sued a vol­un­tary evac­u­a­tion warn­ing.

The storm turned out to be huge, at one point dump­ing more than a half-inch of wa­ter in five min­utes on the fire-baked hill­sides. Of­fi­cials es­ti­mated that some flows rac­ing through neigh­bor­hoods may have been 25 miles per hour and tall enough to en­gulf ve­hi­cles.

Lewin was taken aback by their reach and fe­roc­ity. “We knew we were go­ing to have de­bris flows,” he said. “We never an­tic­i­pated it would be to the de­gree it was.”

Res­i­dent Brent Lar­son, who runs a bou­tique gar­den­ing busi­ness, had heard the warn­ings and knew a flash flood could hit.

His fam­ily’s house, though, was low on the hill, be­low the manda­tory evac­u­a­tion zone and far from the fire scars. So he stayed.

“We’d been evac­u­ated so many times dur­ing the fire sea­son, fam­i­lies were so tired of mov­ing back and forth,” he said. “That is why we were in the house that night.”

He awoke “by the grace of God,” thanks pos­si­bly to a bright light out­side the win­dow from a nearby fire at a bro­ken gas main. He felt a rum­ble and heard trees snap­ping mo­ments be­fore the flow smashed into his house. “We ran to the fur­thest part from where it hit. The fire­place made sense.”

At some point, he no­ticed his cell­phone had re­ceived a warn­ing text from of­fi­cials say­ing: Na­tional Weather Ser­vice flash flood warn­ing for burn ar­eas in Santa Bar­bara County. Take pro­tec­tive ac­tion to stay safe.

County emer­gency op­er­a­tions chief Lewin said the per­cent­age of peo­ple who evac­u­ated was “rel­a­tively low,” partly be­cause of fir­ere­lated “evac­u­a­tion fa­tigue,” partly from lack of pub­lic un­der­stand­ing about de­bris flows.

Bet­ter warn­ings

With fires, “you can smell the smoke, see the flames, you un­der­stand what a fire can do. But in pub­lic re­sponses, they didn’t know that mud can kill,” said Mark Jack­son of the Na­tional Weather Ser­vice.

Of­fi­cials now are de­bat­ing whether bet­ter warn­ings can be is­sued in the fu­ture, based on more pre­cise anal­y­sis of where flows might run and how big they will be.

The U.S. Ge­o­log­i­cal Sur­vey an­nu­ally pub­lishes maps that show which fire-scarred hill­sides they and state of­fi­cials be­lieve are at risk for de­bris flows. The prob­lem, the USGS’ Ja­son Kean said, is “our maps show where the de­bris flows (might) be­gin, not where they go. That is a tool we don’t have yet. That is some­thing that clearly needs to get done.”

UC Berke­ley ge­ol­o­gist Bill Di­et­rich con­tends the tech­niques are avail­able to ac­com­plish that, us­ing li­dar, a com­bi­na­tion of laser and radar, to an­a­lyze to­pog­ra­phy. He said of­fi­cials need to com­mit to us­ing the tech­nol­ogy more widely now.

“The Mon­tecito case is a prime ex­am­ple of a fail­ure to tell where things will go,” he said. Di­et­rich drove through Mon­tecito the day of­fi­cials re­opened the mud­died roads. The flow routes were pre­dictable, he said.

Af­ter the Jan. 9 flood, state of­fi­cials did step in and as­sem­ble maps, as Di­et­rich sug­gests, that show bet­ter guesses of where flows might run. Sim­i­lar work is be­ing done at the Holy Fire site in River­side County.

Santa Bar­bara County now faces an­other high-risk win­ter. County emer­gency chief Lewin has be­gun hold­ing pub­lic meet­ings with the mes­sage to be alert and pre­pared. Have a plan. Heed in­struc­tions. And go when told to.

An early Oc­to­ber rain­storm “trig­gered a lot of emo­tions” on the hill­side, he said. “We know the com­mu­nity has a level of trauma.”

Jack­son of the Na­tional Weather Ser­vice also has been giv­ing pre­sen­ta­tions about de­bris flows. In those talks, he warns that what hap­pened in Santa Bar­bara County last Jan­uary is not a solo event.

“There are other Mon­tecitos around Cal­i­for­nia,” he said.

KATIE FALKEN­BERG / LOS AN­GE­LES TIMES (TNS)

Cal­i­for­nia De­part­ment of Trans­porta­tion work­ers con­tinue to clean up High­way 101 in Mon­tecito on Jan. 15, six days af­ter a de­bris flow in­un­dated the area.

The de­bris flow is al­most as high as the Mon­tecito city sign along High­way 101.

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