By about 3:40 p.m., two of the runways were operating again. About two hours later, all three were back in business. Throughout the day, the airport dealt with a mix of flight diversions, cancellations and delays.
Gann said this was the first time in 24 years the airport had been closed due to ice.
"We are urging passengers to stay home or in their hotel rooms until they can confirm the status of their flights," Gann said, noting that nearby lodging was full because of two major conventions in the area.
Robert Nischwitz, in town for one of the conventions, is used to freezing rain in his hometown of Cincinnati, though even he had a few slips walking around Salt Lake City on Thursday. He never completely fell, though, and advised Utahns not used to such an event to keep their eyes peeled for the shine of ice on the ground, and keep their hands out of their pockets so that they can catch themselves if they slip.
Emergency rooms saw a lot of patients Thursday who came in after a slip on the ice. Seventy people arrived in the emergency room at Utah Valley Regional Medical Center with an ice-related injury, one of whom also died, said spokeswoman Janet Frank, although she didn't provide any details about the death. Slips and falls accounted for the majority of emergency patients at University Hospital as well, and Intermountain Medical Center was "swamped" with patients, according to a Twitter post from spokesman Jess Gomez.
Meanwhile, the Utah Highway Patrol and county and municipal police agencies scrambled to accident scenes even before dawn. No life-threatening injuries were initially reported, but the crashes did leave some drivers hurt.
"We have had a lot of crashes going on this morning throughout the valley," UHP Cpl. Todd Johnson said. "Two people were transported [to the hospital] in one crash on [Interstate 215] near 1500 South on the west side of the [Salt Lake] Valley, but no serious injuries so far."
As of 11:30 a.m. Thursday, three UHP troopers had been involved in crashes while on duty two in Salt Lake County and one in Utah County.
One trooper who was standing outside his car investigating a two-car crash on Interstate 15 near 1000 South was tossed about 10 feet when his cruiser was struck by an oncoming vehicle. He was not believed to have been seriously hurt but was checked at a local hospital, UHP said.
Around 8:30 a.m., another trooper was rear-ended on I-15 near 5300 South and was also taken to a local hospital as a precaution. Further south, a third trooper's car was hit around 9 a.m. on I-15 near a Springville off ramp. The trooper had minor back and neck injuries, but was not taken to a local hospital.
While Johnson estimated UHP had responded to scores of weather-related accidents by mid-morning Thursday, a steady stream of other accidents and slideoffs over 240 in the Salt Lake and Utah valleys combined were reported by Salt Lake and Utah county dispatchers.
The messy roads picked up again in the evening, though dispatchers noted the situation wasn't nearly as severe as the morning. To keep it that way, Layton police put out an auto-dial asking residents to stay off the roads on Thursday night if they could, after they responded to seven accidents within about 20 minutes.
Forecasters characterized the weather Thursday as a freakish climatological event for the desert state.
"Freezing rain is an extremely rare event for us," said NWS meteorologist Monica Traphagan. Since 1940, there have been only 10 recorded events of measurable freezing rain at the Salt Lake City International Airport station.
The water content of Thursday's freezing rain was nine-hundredths of an inch, she added, making it the highest water content for freezing rain measured since 1983. The last time freezing rain was recorded at the airport was January 2005.
Northern Utah school districts reported minor delays for bus routes. Provo cancelled garbage pickup. And a frozen pipe burst at the University of Utah's J. Willard Marriott Library on Thursday morning, damaging a 2,000-square-foot area on the building's first floor.
The pipe burst about 10 a.m., spraying water onto an employee area on the first floor of the building, said U. spokesman Keith Sterling. Officials evacuated the building for about 45 minutes.
"No books were damaged," Sterling said. Crews were assessing the damage to determine the cost of repairs.
Utah Department of Transportation crews were dispatched to spread ice-melting salts onto the slippery roadways. The agency closed Highway 89/91 through Sardine Canyon for a period due to treacherous road surface.
In Salt Lake City, all 45 available plows with sander units were deployed early Thursday morning to apply salt, with priority given to main roads, arterials and steep residential streets, the mayor's office reported. Crews also applied salt to sidewalks in the most trafficked pedestrian areas although walking was still a hazardous activity during the lunch hour.
Tribune reporters Jessica Miller, Michael McFall and Lindsay Whitehurst contributed to this story.
Northern Utah • The three-day forecast calls for mostly cloudy skies Friday and Saturday, with highs in the mid-30s and lows in the mid-20s in Salt Lake, Davis and Weber counties. On Sunday, another storm will bring a 70-80 percent chance of rain and snow, and should clear out the inversion. Highs will range from the mid- to upper 30s.
Southwestern Utah • St. George will be mostly cloudy through Sunday, with highs in the mid-50s and a 30-40 percent chance of daytime precipitation.
Southeastern Utah • Moab will be partly cloudy Friday, with a 50 percent chance of rain and snow Saturday and mostly cloudy on Sunday. Highs will range from 37-40 degrees.
Source • National Weather Service