Two people died early Sunday after two crashes occurred in less than three hours on the northbound 15 Freeway in Rancho Cucamonga, officials said.

The first incident happened around 3 a.m. and involved a car and a big rig, according to the Rancho Cucamonga Fire Department. The agency confirmed the collision resulted in one fatality but provided no further details about the cause.

The Fire Department said slowing traffic at the scene led to another deadly crash at around 5 a.m.

According to the California Highway Patrol, that incident happened on the same freeway near Etiwanda Avenue and involved five vehicles.

The agency said the male driver of a 2013 Toyota Prius was traveling at an unknown speed on the No. 4 lane when he struck the back of a 2005 Ford Escape, causing the second vehicle to slam into the center barrier.

The Prius then came to a rest across the No. 4 and 3 lanes, where the driver side was subsequently hit by an oncoming 2005 Honda Odyssey going about 65 mph, CHP said.

The Prius landed on the No. 3 lane in a northerly direction and was hit in the rear by a 2009 Volvo semi truck, investigators said.

The Toyota's driver was ejected from that impact, and his vehicle ended up down the embankment east of the freeway.

A fifth vehicle passing by, a 2015 Toyota Sienna, was then hit by a piece of debris that shattered the minivan's left rear window.

Fire Department personnel pronounced the driver of the Prius dead at the scene, CHP said. His identity has not been released.

It's unclear whether any of the other drivers involved were injured.