(CNN) -- Winds so strong they knocked over semi trucks have been gusting through parts of Montana and Wyoming.
The National Weather Service issued a wind warning until 11 p.m. Monday for Browning, Montana, where gusts of up to 85 mph were recorded Saturday.
In Cheyenne, Wyoming, gusts of up to 65 mph are expected and a wind advisory is in effect until 5 p.m. Sunday.
Officials warn that driving over mountain passes and on roads running from north to south will be difficult.
Several semi trucks blew over Saturday along Interstate 15, according to CNN Great Falls, Montana, affiliate KRTV. No injuries were reported.
The gusting winds have toppled trees and bent over power poles.
Sustained winds will be between 30 and 50 mph, KRTV reported.