The desert climate and flat landscape found on the stretch of state Route 240 that lies 24 miles west of Richland is ideal for tumbleweed growth, and high wind speeds Tuesday caused thousands upon thousands of them to break from their roots and spin out onto the highway.
Once they were loose, they collected en masse in a portion of the highway that cuts through hills, instead of following the contour of the land.
Calls about the hazard started coming into Washington State Patrol around 6:30 p.m., said public information officer Chris Thorson. Since it was already dark, the drivers were also experiencing poor visibility.
Normally, the best move is to drive through tumbleweeds. But on this night, the 2-mile section of closed-off highway had thousands of tumbleweeds stacked 20 to 30 feet high.
“I spoke to the maintenance supervisor out in the field this morning, and he said that he’s worked here for 20 years and he’s never seen anything like it,” said Summer Derrey, Washington Department of Transportation spokeswoman.
These were the precise conditions that led to what Thorson termed “Tumblegeddon,” a pileup of tumbleweeds on the highway that encased multiple cars and trucks from New Year’s Eve into 2020. WSDOT coordinated with WSP to close off the highway and recover the vehicles trapped inside.
Spokane-born WSP Trooper Sarah Clasen, who had been on scene that evening, said it was like a tumbleweed avalanche. Fittingly, WSDOT performed the rescue with snowplows.
“So, when our plows are in there trying to remove the debris, our plow drivers had to be at speeds around 5 miles per hour so they didn’t hit people or other vehicles,” Derrey said. “The visibility was so low.”
Clasen said that some of the drivers – fearing they would run out of gas – turned off their vehicles but kept their lights on so they would be visible when the snowplow attempted to unearth the vehicles. More than 20 people were rescued from the tumbleweeds, and many rang in the new year waiting in their vehicles.
“Some people were pretty calm, and others were a little bit more panicked,” Clasen said. “And, I mean, a couple cars had kids in them. So obviously, you know, kids get scared if they’re getting covered up by tumbleweeds.”
Derrey said the crews estimate there was 9 million cubic yards of tumbleweed debris (enough to fill 2,754 Olympic-size swimming pools), and most of that was pushed into ditches at the sides of the road. But the debris can’t stay there forever, and she said WSDOT would eventually provide traffic control while the Hanford Fire Department performs a controlled burn of the tumbleweeds. They won’t be able to do that, though, until the wind speed decreases. It is also in close proximity to the Hanford Nuclear Reservation.
A tumbleweed is the name for a structural part of a plant that – when mature and dry – detaches from its stem or root and rolls in the wind, dispersing its seed. There are a few tumbleweed plants, but the tumbleweeds in this situation are likely Russian thistle, said Drew Lyon, Washington State University endowed chair of Small Grains Extension and Research, Weed Science.
“It’s a highly drought-tolerant species, so it germinates early,” Lyon said. “Once it gets its root system established, which it puts a lot of energy in early on, it’s pretty tough to control.”
Lyon said the weed was introduced to the country in the late 1800s by accident, a contaminant in grain or wheat seed from Russia. Lyon said he’s never heard of a tumbleweed incident this large.
“I’ve seen fences pulled down by them because you get so many of them, and they’re so heavy,” Lyon said. “The ranchers have problems because the cattle can get out, and they have to figure out a way to get rid of them.”
Tumbleweeds have long been a nuisance, and the problem could be increasing. In August, Lyon, in conjunction with researchers at University of Idaho and Oregon State University, published in Pacific Northwest Extension Publishing a paper that looked at the problem of variations of Russian thistle becoming resistant to herbicide.
“A lot of growers were using glyphosate to control Russian thistle in their fallow fields, and in 2015 we discovered some biotypes of Russian thistle that the glyphosate no longer controlled at a rate that farmers could afford,” Lyon said. “It’s getting harder and harder to control the weed.”