WENATCHEE — If you live, work, or drive in an area below any of the wildfires in last year’s Wenatchee Complex Fire, you may want to pay extra attention to the rain.
Officials say mudslides and significant debris flows can happen with just a fraction of the rainfall that’s normally needed to cause similar problems.
That’s because the soil isn’t as absorbent, there’s little to no vegetation to hold the soil in place once runoff begins, and the ash in the runoff allows objects to float that normally wouldn’t. Not just mud and debris, but even large rocks and cars have been known to float away, officials said.
Representatives from several local and federal agencies met Wednesday to talk about how to inform the public about this threat that they think will continue for the next three years, and when to initiate a response if any of the thousands of acres burned by fire get hit with a downpour.
Problems are most likely to occur if it rains at least 0.1 of an inch in ten minutes, said Amy Hendershot, Chelan County resource conservationist for the Natural Resources Conservation Service.
No. 1 and No. 2 Canyons above Wenatchee
Crum Canyon, Oklahoma Gulch, Byrd Canyon and Highway 97 below the Byrd Fire
Spray Canyon and Antoine Creek below the Goat Fire
First Creek above Lake Chelan State Park and Granite Creek
“That’s equivalent to, if you were driving down the road and you had to pull over because your windshield wipers couldn’t keep up,” she said. It’s pretty hard rain, and there’s no telling when, or if, it will happen over any of the areas burned by summer’s wildfire areas.
But the possibility is very real, even this week, with a forecast of rain in the Wenatchee Valley through Friday.
The wettest days this week were forecast for Wednesday and today, said Rocco Pelatti, meteorologist for the National Weather Service. He said skies should start to clear by Friday evening, and drier weather is expected to settle in by Sunday.
But flash floods could cause mudslides and debris events any time over the next few years.
Have a plan to evacuate to higher ground
Buy NOAA weather radios, or monitor weather forecasts
Put away or secure items that could be carried away
Encourage natural channels for water to flow
Make sure ditches and drainages are free of debris
Keep a supply of food, water and other emergency needs
Check out www.co.chelan.wa.us/pw/rain_gage.htm or wrh.noaa.gov/otx/ for more information
To help keep watch, the U.S. Geological Survey and Chelan County Public Works installed nine rain gauges in different parts of the Wenatchee Valley. A tenth gauge will be installed on Friday. The gauges are on U.S. Forest Service and state Department of Natural Resource lands up the No. 1 and No. 2 Canyons near Wenatchee, up Mission Creek near Cashmere, Up Oklahoma Gulch near Entiat, and up First Creek near the south shore of Lake Chelan. They act as an early-alert system, sending information to the National Weather Service by radar.
Pelatti said all of the meteorologists at the Weather Service’s Spokane office have been trained on how to watch the gauges, and be ready to issue advisories.
But residents shouldn’t count on any warning, Hendershot said. “Because of the geography of our region, and because the ridgelines are very, very close to the city, there may not be enough time to get an advisory out,” she said. “We don’t want people to think that’s the sole way to get information.”
She said first, residents are urged to be prepared, and have a plan for what they will do if a flash flood hits near their home or workplace.
People are also encouraged to track the weather by buying a NOAA weather radio, monitoring weather forecasts, following the National Weather Service on Facebook and Twitter, and using smartphone applications.
“The best thing you can do to prepare your home and family for potential flash-flooding,” Hendershot said, “is to educate yourself before it happens. Have food, water and other necessary items available.”
Agencies have also been preparing for the possibility of flash floods.
The Natural Resources Conservation Service, Chelan County Public Works, and the Chelan County Natural Resources Department have cleaned out and replaced culverts and improved drainages.
Hendershot said the threat will remain for the next three years, although it will be reduced as time goes on, and vegetation begins to grow back and the soil becomes more absorbent.
“We don’t want to cry wolf,” she said. “But there is a risk. And there have been situations in other areas of the country that have had significant events from ash, mud, water and debris coming down,” she said. “It’s just critical for residents to protect themselves, and be prepared.”
K.C. Mehaffey: 997-2512