LARAMIE, WYO. ? At least 20 vehicles crashed Sunday on a rural Wyoming interstate in blizzard conditions, killing at least six people, officials said.

An undetermined number of injured victims were taken to hospitals in Laramie and Rawlins, the Wyoming Highway Patrol said. Troopers didn’t know whether there were additional fatalities or injuries because they had not reached all the vehicles late Sunday, Sgt. Stephen Townsend said.

Troopers at the scene reported zero visibility due to strong winds and blowing snow. Interstate 80 was closed for about 100 miles from Cheyenne to Rawlins.

The crash, which involved semitrailers and passenger vehicles, was reported shortly after 4 p.m. west of Laramie. Few other details were released. Several smaller crashes also occurred behind the 20-vehicle crash, troopers said.

Part of I-80 was closed because of the blizzard conditions, and about 50 miles of interstate from Cheyenne to Laramie was closed at the request of Laramie officials, who said there was no parking left in the town for semitrailers.

The highway patrol also closed U.S. Highway 30 in the Laramie area – which often serves as a detour for I-80 – because of the weather and reports of crashes.