Wicked Wildfires with Wet Weather…Watershed Woes

Wicked wildfires and frightful floods are a natural and challenging part of the ecological cycle here in California. Fire is essential in Mediterranean ecosystems with certain species of native plants needing fire to guarantee their existence. All too often, however, these fires take place in the fall when the flames are fanned by fierce Santa Ana winds that hauntingly howl through our canyons. These fires leave behind ashy moonscapes and barren areas of land devoid of vegetation. It is these desolate landscapes onto which winter’s first raindrops fall, and while rain is always welcomed here in Southern California, vast areas without groundcover mixed with heavy rain produces a new threat – mudslides. The fact that a high percentage of Los Angeles neighborhoods are within the Wildland Urban Interface (or WUI) – areas where homes meet forest or wildland – California’s fire and flood cycle presents homeowners with added challenges.

The recent Station Fire vividly demonstrated the devastating impact that fire can have here in the Southland. It claimed two lives, destroyed dozens of homes and scorched a staggering 250 square miles in the foothill communities of La Canada-Flintridge, Altadena, Pasadena and Angeles National Forest. The next challenge we face with an El Niño winter predicted is the increased potential for flooding and mudslides. Barren hillsides and increased rainfall create a calamitous combination for destructive debris flows that can threaten communities, clog our storm drain system and create flooding in LA’s watersheds.

In September, Burned Area Emergency Response (BAER) teams from the U.S. Forest Service assessed the burn area and its potential for mudslides. The LA Times reported that scientists’ concern revolves around a process called “entraining” which is when rain falls on bare ground and washes away topsoil, sand, small rocks and burned plant material creating an unstoppable avalanche.

“As a result of the recent wildfires there will likely be a larger than normal quantity of debris and pollutants captured by our storm drains this winter,” says Robert Potter, with the City of Los Angeles Bureau of Sanitation. He adds, “In preparation for this season’s rain, all City-owned catch basins and debris basins have been cleaned to minimize the possibility of flooding. Sanitation crews will be ready to respond to storm-related emergencies should they occur.”

Earlier this month, the U.S. Geological Survey (USGS) issued a study stating that rainstorms could cause massive debris flows in our local waterways with even the slightest rain falls in the San Gabriel mountains this winter.

“We have calculated really high probabilities of really big flows,” said Susan Cannon, a geologist for the USGS. “Some of the areas burned by the Station Fire show the highest likelihood for big debris flows I’ve ever seen.”

Although the Station Fire has ceased, LA’s fire season is far from over and our rainy season is just beginning. Residents can do their part to prepare.

Fire Preparedness and Prevention:
– Develop a home fire evacuation plan and discuss it with your family.
– Create a defensible space around your home. Manage the vegetation surrounding your property by removing dead plants and maintaining a 200 foot perimeter between structures and foliage.
– Keep rooftops and gutters free of flammable debris such as leaves or pine cones.
– Heed evacuation order when issued by authorities.

Flooding Preparedness and Prevention:
– Remove or secure loose debris on your property to prevent it from entering our waterways.
– Avoid outdoor watering on rainy days to conserve water and prevent street flooding.
– Use sand bags to direct mud flows away from property.

While the fires and floods here in Southern California are part of a natural cycle we have little control over, we can prepare and minimize their potentially devastating impacts. “The City is a partner with residents,” Potter said. “Together we can promote public health and safety during LA’s fire and flood season.”

For information about fire prevention tips:

Public Works Department Residential Advisory Site: http://dpw.lacounty.gov/care/

City of LA Fire Department: http://lafd.org/

US Forest Service: http://www.fs.fed.us/fire/prev_ed/prevention/index.html

LA County Fire Department: http://www.fire.lacounty.gov/

For information about the connection between fires, flooding and water quality:

Los Angeles Times: Concerns rise about mudslides in areas burned by Station Fire

LA Creek Freak: Invasive plants: like pouring oil on water – and setting it on fire

Rambling LA Blog: Nature-loving Southern Californians are endangering the landscapes they love

National Public Radio: Long Recovery in Store for Scorched Calif. Hillsides

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Comments (1)

  1. Avatar for LA Stormwater
    Realtor from Toronto
    October 31st, 2009 at 5:43 am

    To avoid the landslides more trees need to be planted every year. I see how that could be difficult with the risk of fires but trees prevent many of the catastrophes that you mentioned. Good luck!

    Julie

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