Updated 1:29 p.m.:
A California Highway Patrol officer struck by a car while investigating a crash on the westbound 60 Freeway on the edge of the Badlands was one of four people seriously injured, authorities said.
"While attending a victim of the traffic collision, an additional vehicle entered the scene and impacted emergency vehicles," reads a statement released by Cal Fire/Riverside County fire.
According to the CHP, the officer was on scene with medics and firefighters, tending to a woman who had crashed in her Chevrolet sedan on the 60 and ended up on the Perris Boulevard exit ramp.
She suffered serious injuries.
"While they're investigating that collision, another vehicle goes out of control," said CHP information officer Steve Carapia.
The 2009 Toyota sedan slid and veered onto the exit ramp as well, clipping an ambulance, which in turn struck the officer and a relative of the first driver, Carapia told Patch.
The Toyota continued to overturn onto a Moreno Valley fire truck, the officer told Patch.
The 2009 Toyota driver suffered major injuries, as did the first woman's relative, the officer said.
The CHP officer suffered serious injuries and was taken to Riverside Community Hospital.
The causes of both crashes were under investigation.
"Obviously it was wet out there," Carapia told Patch.
An injury crash on SR 60 Monday stalled traffic on the westbound side for about four hours, the CHP reported.
A SigAlert was issued for the crash, reported about 8 a.m. on the westbound side, at Perris Boulevard.
Traffic into the Badlands was affected by the closure.
The carpool lane was reopened at about 12:30 p.m., the CHP reported.
The cause of the crash was under investigation and a condition report was not immediately available.