Residents urged to heed flood warnings
While many areas burned in the Cedar Creek Fire now have hydrophobic, or water-repellant soils, and could be at risk for post-fire flooding, the areas are not at high enough risk to be eligible for the federal Emergency Watershed Protection program, a representative from the National Resources Conservation Service said last week.
The Okanogan County Conservation hosted a meeting Wednesday (Oct. 27) to discuss post-fire flood risk in the area burned by the Cedar Creek Fire, which included speakers from the National Resources Conservation Office, the National Weather Service and the Federal Emergency Management agency.
This is the second recent meeting to discuss flood and debris-flow danger downhill from burned areas. On Sept. 22, the same group of agencies, along with the U.S. Geological Survey and the U.S. Forest Service, gathered to discuss the Forest Service’s Burned Area Emergency Response report, which found that more than 40 percent of soil in the Cub and Cedar Creek wildfire areas was likely hydrophobic, or likely to not absorb water in a rain event. That could lead to excess runoff, and in extreme cases, mudflows and flash floods, they reported.
Joe Lange, state design engineer at the United States Department of Agriculture’s National Resources Conservation Service, gave an overview of his office’s Emergency Watershed Protection program Wednesday.
The EWP can fund projects to remove debris from streams and culverts, reshape and protect eroded streambanks, repair levees and other projects in areas affected by natural disasters, such as fires and floods. NRCS determines whether areas qualify for the EWP program by conducting studies and modeling for pre- and post-fire conditions.
The models determine how much an area could flood under set conditions, and the post-fire risk compared to the pre-fire risk. An area only qualifies for the EWP program if there is a significant increase in risk post-fire, compared to pre-fire conditions.
“Since post-fire flood has not yet occurred, the assessment relies on hydrologic and hydraulic models to determine what could occur sometime in the future,” Lange said.
Lange noted that models are often not 100% accurate. Soil moisture, water repellent soils, rain and snow, storm distribution and other variables can affect the accuracy of the predictions, he said.
The study assessed post-fire flood risk in nine areas affected by the Cedar Creek Fire: Wilson Ranch Road, Looney Creek, Davelaar Drive, Alpine Valley Lane, Little Boulder Creek, Wolf Creek Road, Wolf Creek, Thompson Creek at Mugo Road and Thompson Creek at South Black Jack Road.
None of the areas showed a high enough increase in flood risk post-fire in the next few years based on the models to be eligible for the EWP program, Lange said.
“There could be significant increases in runoff from post fire effects if it rains a lot in a relatively short period of time and within the next few years,” Lange said. “Any areas could be flooded, however many of those areas could be flooded in pre-fire conditions.”
That doesn’t mean residents should ignore flooding risk, he said.
“If you have a house located in a flood plain such as an alluvial fan, your life may be at risk,” Lange said. “This is true for both pre-fire and post-fire conditions.”
Robin Fox, of the National Weather Service’s Spokane office, said the rainstorm on Sunday (Oct. 24) dropped an inch to an inch and a half of rain on Winthrop and Mazama, but said the agency didn’t receive significant reports of flooding.
“We’re keeping our sights on heavy rain events,” she said “We’ve had a lot of wet weather the last several weeks and that is normal for this time of year. But it seems a little abnormal since we’ve had such a long stretch of dry weather.”
Organizations participating in the meeting urged residents in burned areas, especially those downhill from burned areas, to consider flood insurance from the Federal Emergency Management Agency’s National Fire Insurance Program, and to have a plan in the event of a flood warning. For more information on insurance, go to www.fema.gov.