Costa Mesa intersection closed for 6 hours after truck driver dies in violent crash

Police closed a Costa Mesa intersection after a violent collision overturned a commercial truck and killed its driver. 
The crash happened at Sunflower Avenue and Fairview Road sometime before 9:27 a.m. — when the Costa Mesa Police Department announced the closure on X. 
When fire responders arrived, they found the truck lying on the passenger side. The front of the truck sustained serious damage, with the engine bay exposed. 
Police said the driver was pronounced dead at the scene. The department announced an estimated six-hour closure to allow crews to clean up the debris and for investigators to canvas the scene.
The cause of the crash is unclear.