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Already beset by fire, New Mexico braces for weeks of flash floods

By Greg Botelho, CNN
The Las Conchas fire still burns around Los Alamos. It's about 45 percent contained. The area is now under a flash flood watch.
The Las Conchas fire still burns around Los Alamos. It's about 45 percent contained. The area is now under a flash flood watch.
  • The Las Conchas fire is 45 percent contained, having burned more than 146,000 acres
  • As the fire rages, a flash flood watch is issued for northern and central New Mexico
  • An official notes that in places there's no vegetation to contain intense rainwater
  • A meteorologist says fire-scarred areas seem water-repellent, acting like pavement

(CNN) -- If the still raging fires didn't destroy their homes, New Mexico residents could be done in by flash flooding this monsoon season -- the ravaged landscape heightening the danger, and likelihood, of mudslides and other problems.

Despite rain over the weekend, the Las Conchas fire continues to burn around Los Alamos. Nearly 1,900 personnel have worked to contain 45 percent of a blaze that's scorched more than 146,000 acres and more than 100 buildings, according to the website of the federal Interagency Management Team that is overseeing the firefight.

With monsoon season having just kicked off, more precipitation could help firefighters contain the wildfire, one of several still burning in the Southwest. Yet it is not all good news, as torrential downpours -- which will likely occur into September -- may also cause further ruin in already hard-hit areas.

"It will simply take just one thunderstorm in the right area of a burn scar to potentially have devastating affects," National Weather Service meteorologist Kerry Jones said. "That could happen tomorrow or Tuesday, or a month from now, or both."

Robyn Broyles, a spokeswoman for the U.S. Department of Interior's Burned Area Emergency Rehabilitation team, explained that forests, shrubs and other flora generally mitigate the impact of monsoon rains.

Los Alamos residents can go home

Such plant life largely has been charred and flattened by the weeks-long Las Conchas fire. And the fact that the fire has affected acres upon acres of hilly, mountainous terrain makes fast-moving mudslides even more dangerous -- and likely.

"There's no vegetation left on the landscape to keep the water in place when the monsoon hits," Broyles said.

Jones added, in an e-mail to CNN, that "severely burned soil can be a water repellent" and effectively act like pavement, with water quickly flowing over it and bringing ash, silt, sand and assorted debris along with it.

"(Those mudslides) then may damage or destroy culverts, bridges, roads and buildings, potentially causing injury or death," he explained.

That danger is imminent in northern and central New Mexico.

A monsoon "burst," meaning a period of intense rain, was expected Monday and Tuesday in the area that's been a hotbed for wildfires since last month, said Jones.

That's why the weather service issued a flash flood watch into Monday evening for a large swath of New Mexico including the Jemez and Sangre de Cristo mountains. Between a half inch to an inch of rain could fall within 30 minutes at times.

Still, even though it is now monsoon season, that does not mean that new fires couldn't break out or that old ones could not continue to spread.

As Jones noted, there likely will be "breaks" over the summer with little to no precipitation, and possibly high temperatures and strong winds. On Sunday night at Los Alamos Airport, for instance, the humidity was 18% to 20%, the weather service said -- even though thunderstorms could hit within hours.

That continued wildfire danger is why Albuquerque and Bernalillo County continue to keep the Bosque, Rio Grande Valley State Park and all open space areas closed to the public -- even with rains on the way -- the city's website reports.