"The danger is for semis, campers," Gleason said. "That's why we're prohibiting them. Message signs will be out warning them of dangerous high winds."
According to Gleason, winds of up to 60 mph can topple a semi trailer. As of early Thursday evening, wind had not damaged or toppled any high profile vehicles. Officials did not know when the roads would be re-opened to those vehicles.
Smaller vehicles are not included in the closure.
The intense guests comes after the NWS issued a High Wind Warning and Alert for northern Utah's Weber, Davis and Salt Lake counties beginning 4 p.m. Thursday and extending through noon on Saturday. The region braced for steady winds of 30-40 mph with gusts topping a hurricane-force 70 mph.
Traphagan said much of the northern Wasatch Front had experienced winds of about 40 mph or less Thursday afternoon.
The windy weather is the result of a low pressure system in southern California, Traphagan explained. She said air circulates around the system counter clockwise, creating unusual eastern winds in Utah. Davis County and areas north of Salt Lake City are particularly impacted by the system due to topography and the alignment of mountains.
The state's mountainous spine, from the Idaho border stretching south and west to the Arizona border, along with northwestern Utah's Uintas, began Thursday under a Winter Weather Advisory. Snowfall of 4-8 inches was predicted in higher elevations by the time the advisory expired at noon Thursday.
The Utah Avalanche Center took note of the weather forecast, putting the state's mountains under a "moderate" rating for the risk of potentially deadly snow slides.
The Wasatch Front expected Friday's daytime high temperatures to settle in the mid- to upper 40s, the same range as forecast for Thursday. Overnight lows were to dip into the 20s.
Southern Utah was looking for rain and wind as highs dipped into the upper 50s and overnight temperatures slid into the low 40s.
For more extensive, region by region breakdowns of the weather, visit the Tribune's weather page at this link: http://www.sltrib.com/weather