A 27-year-old pregnant woman was killed in a car accident near North Bend Sunday night.

According to Washington State Patrol, Alyssa Helfenstein was with her family, who are from Moses Lake, when their 2005 Mitsubishi Galant left the roadway and struck a guardrail on the left shoulder and came to a stop in an embankment 20 feet below.

The family was driving eastbound on Interstate-90 near North Bend at approximately 7:25 p.m.

Helfenstein’s husband and two children ages 3 and 5 were taken to Harborview Medical Center with minor injuries.

Troopers are investigating the cause but believe the car was traveling at speeds too fast for weather conditions.

Washington State Department of Transportation reported temperatures to be freezing at the time of the accident. Other news outlets have also reported extreme snow and hail on Snoqualmie Pass Sunday evening.