A bus heading to San Ramon's Bishop Ranch neighborhood was among the four vehicles that collided amid wet weather conditions near the BART station in Walnut Creek on Thursday, with at least two passengers onboard among the five people who were taken to a hospital for treatment of minor to critical injuries.

Steve Hill, public information officer for the Contra Costa Fire Protection District, said that 10 passengers aboard the southbound bus from Walnut Creek were evaluated for injuries by first responders, with at least two and potentially three being transported to a nearby hospital.

In total, Hill said there was one critical injury, one moderate to critical injury and three minor injury cases resulting from the four-vehicle collision.

Firefighters headed to the scene of the crash at Ygnacio Valley Road and Oakland Boulevard at 4:20 p.m. Thursday, reporting that they had cleared the scene at 5:48 p.m., the district reported on Twitter that day.

Although the official cause of the collision is being investigated by the Walnut Creek Police Department, Hill said that with multiple collisions in the area amid the recent rain, Con Fire was warning drivers to avoid speeding and be particularly cautious while driving in wet weather under the current atmospheric river serving as the latest in a series of winter storms.