This is an archived article that was published on sltrib.com in 2015, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

A winter storm system tightened its grip on Utah's northern, central and southern mountains Tuesday, and that higher-elevation snow and valley rain was to continue into the midweek.

The National Weather Service issued a Winter Storm Warning through 4 p.m. Tuesday for the Wasatch Mountains south of Interstate 80, as well as the western Uintas. Snowfall of 8-16 inches was predicted, with the Cottonwood canyons — where 4-wheel-drive or tire chains were required during the commute Tuesday morning — and I-80's Parleys Summit expected to be hit hard.

At mid-morning, white-out conditions were reported along some northern Utah routes. I-84, from just east of Morgan, was closed. As the storm brought traffic to a crawl, the Utah Department of Transportation diverted U.S. 89 southbound traffic onto westbound I-84, south of Ogden.

Utah Highway Patrol Sgt. Todd Royce said that as of late Tuesday morning, about 40 snow-related crashes and slideoffs had been reported in the Weber-Davis-Salt Lake counties corridor. None of those accidents involved serious injuries.

"We anticipated this storm, so we have a lot of troopers out today. They are staying busy," Royce said.

Late Tuesday morning, as the storm slammed into Wyoming, authorities closed down I-80 eastbound between Evanston and Rock Springs.

In the Salt Lake Valley, meanwhile, more than 50 accidents were reported by dispatchers within a three-hour period of the storm Tuesday morning.

A Winter Weather Advisory was in place for the Wasatch Plateau, the Book Cliffs and central Utah mountains, also until 4 p.m. Tuesday. Accumulations of 12-22 inches of snow were predicted. Motorists were warned to exercise care on icy, snow-clogged sections of U.S. 40 over Daniels Summit, U.S. 6 over Soldiers Summit and the higher passes of I-70 and I-15 in the state's midsection.

Salt Lake and Tooele counties also looked for snow of 1-3 inches on the valley floors to 6 inches or more on the benches. Wednesday's high temperatures were to be in the upper-30s to low-40s, mirroring Tuesday's forecast.

The mountains of southwestern Utah, seldom subject to heavy snows, earned an Avalanche Warning through early Wednesday morning. Backcountry winter sports enthusiasts were urged to avoid slopes steeper than 30 degrees, and to ski clear of snowy overhangs.

Wednesday's highs in Utah's Dixie were to range into low- to mid-50s, same as on Tuesday, but precipitation in the St. George area was expected to mostly come in the form of rainfall.

The Utah Avalanche Center also rated the southeastern mountains of Moab at "high" risk for potentially deadly snowslides, while the remainder of the state's mountain monitoring districts earned "considerable" avalanche risk grades.

One bright point, though: all that storm activity was scrubbing the air over Utah's urban valleys. All stations were rated "green," or healthy by the Utah Division of Air Quality through the midweek.

For more extensive forecast breakdowns visit the Tribune weather page at http://www.sltrib.com/weather/.

Twitter: @remims