Motorists in widely dispersed parts of the country found themselves slipping and sliding over the last week in treacherous black-ice conditions. Hundreds of accidents and more than a dozen deaths were reported. Repeated shots of cold, shallow surface air pouring across much of the United States this winter are paving the way for multiple icing events. In a typical year, icy and snowy roads cause roughly 900 U.S. deaths, more than hurricanes, lightning, tornadoes, and floods combined. Ice on highways is an underappreciated, hard-to-predict threat, often lumped in with snowstorms yet distinctly different in its appearance and impact. The events of the last week were striking in their far-flung nature, and a spate of dramatic photos and videos showed millions of people what can happen when vehicles moving at highway speeds encounter ice.
Perhaps the most spectacular multi-vehicle pileup this month was the catastrophic wreck on January 11 along Interstate 94 near Battle Creek, Michigan, which involved nearly 200 vehicles, killed at least one person, and injured many others. The extended chain-reaction accident occurred in poor visibility and road conditions during heavy lake-effect snow squalls. In contrast to that wreck, several other deadly collisions over the last few days occurred in conjunction with freezing rain, drizzle, and fog. These conditions can be far more dangerous than packed snow, in part because the resulting ice buildup on roads can occur in unpredictable patches and can be difficult or impossible for motorists to see.
Figure 1. Temperature at various heights as measured in the National Weather Service radiosonde launched near New York City at 7:00 a.m. EDT on Sunday morning, January 18. Image courtesy Tom Niziol, The Weather Channel.
Sunday’s string of accidents from Philadelphia to New York–dubbed #Icezilla on Twitter—caused major havoc, with at least three deaths and more than 400 collisions across the area. The meteorological set-up on Sunday morning epitomizes how difficult it can be to predict ice. As a strong upper-level trough approached a coastal warm front, rain developed over parts of the Northeast, and warmer air flowed over a surface air mass that had kept readings in the teens and 20s for more than a day. The Weather Channel’s Tom Niziol created the table in Figure 1 using radiosonde data collected from the launch at 12Z (7:00 a.m. EDT) on Sunday morning, January 18. Only in the lowest 200 feet or so of the atmosphere were temperatures below freezing, too shallow a layer for raindrops to freeze into ice pellets before hitting the ground. The icing risk was greatly exacerbated by the preexisting cold, which chilled roadways enough so that some surfaces remained below freezing for a time even after the surface air warmed above 32°F. Later in the day, as a surface low intensified, temperatures at ground level finally warmed up while the rains increased and spread northeastward. Philadelphia saw its seventh-wettest January day on record (1.84”), and a narrow band of thunderstorms gave parts of the New York metroplex a rare midwinter encounter with thunder, lightning, heavy rain, and stout winds.
Figure 2. Black ice is believed to be the cause of a freeway pileup involving more than a dozen tractor-trailers on January 17 along Interstate 84 in eastern Oregon, police said. Photo credit: AP Photo/Oregon Department of Transportation.
Another multi-vehicle pileup, this one in black ice and fog, occurred on Interstate 84 southeast of Baker City, Oregon, on Saturday morning, January 17. The 26-car accident injured 12 people, and a truly phenomenal image of one survivor quickly became iconic. As one semi-truck ran into another, Kaleb Whitbey and his SUV were sandwiched in between. Amazingly, Whitbey escaped with only minor injuries. “I’ve got two Band-Aids on my right ring finger,” he told the Oregonian, “and a little bit of ice on my left eye.”
The nation’s deadliest accident so far this year occurred on Wednesday, January 14, as a truck carrying prisoners and guards from a Texas correctional facility slipped off Interstate 10 just west of Odessa and careened into a train. Eight prisoners and two guards died, with five other prisoners and guards injured. Odessa-Schlemeyer Field reported freezing fog but only a trace of precipitation on the day of the accident, with the NWS’s Midland-Odessa office noting light freezing drizzle across the area in its early-morning forecast discussion. The Texas Department of Highway Safety concluded that icy roads likely led to the accident, while the National Transportation Safety Board is investigating the wreck.
Icing events can be subtle and exceedingly hard to predict, yet they lead to many hundreds of injuries and deaths on our nation’s highways each winter. Even the most prudent motorist can happen upon black ice without warning and find himself or herself virtually helpless to change course. A good deal of useful background, including photos and videos specific to recognizing and dealing with icy roads (as opposed to snow-packed conditions) can be found in the short online course offered at the website icyroadsafety.com. As always, the best strategy is avoidance: waiting till the roads are clearly safe, especially if rain or drizzle is falling onto highways that have been well below freezing for hours or days.
Figure 3. Salting a roadway near Breckenridge, Michigan, to combat icy conditions on November 22, 2014. (WunderPhoto credit: sterlingbreck)
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