WILLOW CREEK, Humboldt County, Calif., Sept. 24, 2026 — A semi-truck and three other vehicles collided on Wednesday evening, September 23, on State Route 299 near Willow Creek, according to the California Highway Patrol. At least one person was reported trapped, and both lanes of the highway were closed for hours.
The crash near postmile 19 involved a semi-truck, an older Toyota Camry, a Nissan Rogue, and a dark-colored Dodge Durango. Radio traffic described heavy smoke at the scene and fuel spreading across the roadway. A trailer hauling mules, reported separately as an animal trailer, was also involved and came to rest on its side.
The driver of the semi-truck was reportedly pinned in the cab, and fire crews were asked to bring extrication equipment. Callers also described two propane tanks leaking near the wreckage and an open battery casing close to leaking fuel, prompting a request for confirmation on whether hazardous materials had reached the roadway. The extent of injuries had not been released as crews worked the scene.
All four vehicles were described as blocking or obstructing traffic, and backups built in both directions before the highway was fully closed. Traffic was still being diverted as of early evening, and the California Highway Patrol had not said when the route would reopen.
The cause of the crash remains under investigation. It was not immediately clear whether the semi struck one or more of the other vehicles before or after they collided with each other.
We hope all those involved have a smooth recovery.
Why Multi-Vehicle Pileups on Highways Like Rte 299 Turn So Severe
A pileup is really a series of separate collisions stacked in seconds. Once the first vehicle slows or stops in a travel lane, everything behind it is closing at highway speed with little distance to react. A semi-truck weighing tens of thousands of pounds cannot stop as quickly as a passenger car, so when a big rig is part of the chain, the impact energy delivered to smaller vehicles multiplies fast.
Reduced visibility is usually the hidden trigger. Smoke, fog, dust, or glare can hide a stopped or slowing vehicle until the gap has closed to almost nothing. Drivers who can't see the hazard ahead don't brake early or steer around it; they arrive at full speed and add their own vehicle to the wreckage already in the road. That's part of why crashes involving smoke or blocked sightlines frequently pull in three, four, or more vehicles rather than just two.
Passenger cars are built with crumple zones at the front and rear designed to absorb a single, planned impact. They are not designed to absorb a second or third hit from a different direction, or the weight of a commercial trailer. Seatbelts and airbags help with the first collision; they cannot undo the physics of a car caught between a stopped vehicle and a heavy truck still moving.
According to the National Highway Traffic Safety Administration, 2,979 passenger-car occupants were killed in two-vehicle crashes involving a passenger car and a light truck in 2023.
Frequently Asked Questions
Are secondary crashes common after an initial wreck?
Yes. Traffic that suddenly slows or stops behind an earlier collision creates a fresh hazard, and vehicles arriving at normal speed usually can't stop in time, adding new impacts to the same scene.
What makes multi-vehicle crashes hard to investigate?
Investigators have to work out the order of impacts among several vehicles, usually using damage patterns, skid marks, and witness accounts, since more vehicles mean more variables and more conflicting statements.
What typically causes pileups involving several vehicles?
Common factors include sudden braking, reduced visibility from smoke or weather, and following distances that don't leave enough room to stop once one vehicle in the chain slows unexpectedly.
Why do chain-reaction crashes happen so quickly?
Each vehicle that can't stop in time adds to the pile, and the process can unfold in just a few seconds once the first hazard appears in a driver's path.
What to Do After a Multi-Vehicle Crash in Willow Creek, CA
If you're involved in or come upon a multi-vehicle crash, try to move to a safe spot away from traffic lanes if your vehicle is able to move, and turn on hazard lights. Call 911 and give as clear a location as possible, especially on a rural highway where mile markers matter.
Even if you feel fine, get checked by a medical provider afterward. Adrenaline can mask pain from a jolt or impact, and some injuries don't show symptoms right away. Keep a record of what you saw and any vehicles involved, since multi-vehicle crashes usually take investigators longer to sort out. If a highway closure affects your route, follow official detour instructions rather than trying to navigate around the scene yourself.
