An unusual summer "whiteout" caused by salt dust spreading across Highway 1 led to a collision that involved 16 vehicles in southwestern Saskatchewan last week, police say.

RCMP received several 911 calls just before 3 p.m. on Sept. 5 about a multi-vehicle crash around five kilometres west of Morse, according to a Tuesday news release.

The road conditions were "near whiteout due to high winds blowing salt residue from a dry lake bed," RCMP said, and visibility was less than 15 metres.

The highway runs along the edge of Reed Lake.

Amie Lewis, who was a passenger in a vehicle travelling eastbound back to Regina from Calgary that hit the weather anomaly, said that's an apt description of the driving conditions.

"You couldn't see anything," she said.

"It was as bad as, probably, the worst blizzard I've been in … but for seconds."

The conditions would go from clear one moment to blinding for a few seconds, then back to the bright, sunny conditions from moments before, Lewis explained.

It resembled a dust storm more than a blizzard, she said, though it was much more dense.

"We were driving in sun, a bright sun because it was quite a warm day, and then this whiteout came out of nowhere, and then it was gone," she said.

"None of us had ever seen anything like this before, so it was an interesting occurrence to be a part of."

LISTEN | Sask. woman says salt dust whiteout unlike anything she's ever experienced:

Lewis said their vehicle was about 20 vehicles back from the accident scene and arrived before emergency services did.

Their vehicle and others were turned around to avoid the accident, she said.

RCMP confirmed that at the time, traffic control diverted vehicles away from the site.

Lewis said the area affected appeared to be about 40 or 50 metres wide and said she believed all of the vehicles in the collision were within that range.

Several people were taken to hospital by emergency services, but none had life-threatening injuries, according to RCMP. There were no fatalities.

STARS air ambulance was called to the collision, the service said, but was ultimately told to stand down by ground emergency services because it was no longer required.