Magnesium chloride: an invited guest
EDITOR’S NOTE – This is the first installment in a five-part series about magnesium chloride, the controversial highway de-icer. Coming Tuesday: An examination of the effects of the road treatments on the environment.
SUMMIT COUNTY – During the winter of 1994-95, the mountain corridor of Interstate 70 closed a record 42 times. And those closures weren’t minor – some of them lasted eight hours or more. Stranded travelers snatched up rooms at mountain hotels, spent nights in their cars or slept on cots set up on an emergency basis in the Summit High School gymnasium and other impromptu shelters.
A string of those closures hit at the worst time possible – on Sundays, usually about the time the ski areas closed and Denver-area residents flooded the snowy highway.
The public relations fallout was disastrous.
With each closure, Summit County’s ski areas lost one-third of their anticipated daily skiers. Eagle County ski areas were hard hit also, though Aspen – which gets many of its skiers from planes and not cars – didn’t take such a blow. Front Range skiers, watching coverage of the closures on television, often opted to stay home rather than risk the unpredictable drive to the ski areas and back.
Magnesium chloride changed all that, Colorado Department of Transportation officials say.
CDOT road crews began spraying it on I-70 through Summit and Eagle counties in 1996, and since then, lengthy closures have become rare rather than commonplace.
During the winter of 1996-97, the interstate closed 17 times. Since then, the number of yearly closures has hovered close to the average of a dozen per season.
“The big thing has been mag chloride,” said Ed Fink, who in the mid-1990s was CDOT’s mountain-area superintendent and is now superintendent for the whole state. “It lasts longer and will persist. The salt and sand technology just didn’t cut it. Mag chloride keeps us from building snowpack and helps us avoid black ice. Snow and ice can’t get bonded to the pavement. That is just extremely important.
“(Before mag chloride), our plows would get caught in traffic (during storms). They couldn’t move, and that’s when we’d have those big closures. It’s rare you see one of those all-night closures we used to have.”
A mid-March snowstorm closed the interstate between Summit County and the outskirts of Denver for just over two days, but that was largely a consequence of the huge volume of snow and the resulting avalanche danger on the highway.
CDOT employees aren’t the only ones who say magnesium chloride has made a difference on I-70. Eagle County administrator Jack Ingstad believes magnesium chloride has saved countless lives. Ingstad lived in Eagle County in the 1970s, “when we had nothing on the surface, and there were a ton of accidents and deaths on I-70.”
“Drivers back then drove 15 to 20 mph on Vail Pass. You needed to, because you never knew when you were coming around the corner to black ice.”
Those accidents, and certainly those low speeds, are no longer the norm on Vail Pass.
CDOT’s recipe for better roads
While magnesium chloride may have been the magic ingredient in CDOT’s reduced closure rate, it wasn’t the only cause. After that record-setting ’94-’95 season, CDOT sank $7.3 million into efforts to minimize the numbers of closures. The department bumped up staff, luring workers with increased pay and a beefier benefits package. It built pull-over areas along I-70 so truckers could easily stop and affix chains to their tires when the chain law was in effect. And it supported a tougher chain law later approved by the state Legislature.
While CDOT pointed much of the blame for the closures at truckers, the trucking industry was one of the groups most angry about the conditions. Worried about hours spent on the shoulder of the closed interstate and the resulting missed delivery deadlines, truckers were as vocal – if not more so – than ski area higher-ups, said former CDOT spokesman Dan Hopkins.
The pressure to improve conditions was intense, Fink added.
“We had our marching orders from our executive director, the Governor’s Office and the ski industry,” he said. “It was rough.”
Now a spokesman for Gov. Bill Owens, Hopkins was, in the mid-90s, appearing with what was for him uncomfortable frequency on TV and radio airwaves defending CDOT. Like Fink, he says magnesium chloride made the greatest change in road conditions. Another important factor: CDOT invested a lot of money in information boards and phone lines to let travelers know in advance about road conditions, Hopkins said.
“We never even got close to those numbers (of closures) after that,” he said.
And while some people say freezing magnesium chloride actually makes roads icier, CDOT officials say that just isn’t true.
The mixture sprayed on the roads that includes magnesium chloride is 70 percent water, said CDOT spokeswoman Stacy Stegman, but, “Mag chloride lowers the freezing point of water, so the chance anything is going to freeze is much, much less than (without mag chloride).
All de-icers contain water, Stegman said, but in varying concentrations.
“Mag chloride is no different than any other product that’s out there,” she said.
While the addition of magnesium chloride might have helped the ski areas’ bottom line, it hasn’t helped CDOT’s. Costs per mile to plow roads are up 75 percent since CDOT started using mag chloride.
How Magnesium Chloride is Applied
– Colorado Department of Transportation (CDOT) drivers apply the material before snow starts sticking to the road, generally when the road temp is below 35 degrees
Fahrenheit and falling and while it is snowing. (This is the anti-icing phase.)
– If precipitation is light, CDOT may reapply the material to “de-ice” any snow and ice that is beginning to form to keep the road wet.
– If precipitation is moderate to heavy or very cold temperatures descend, CDOT will return to plowing and sanding until the temperature increases and snow stops or greatly reduces in intensity.
– When temperatures are warmer and snow is light or not falling, CDOT drivers will plow off everything they can and then de-ice the road and return it to bare (wet) pavement. Many times CDOT drivers are successful in performing
de-icing before the ski traffic starts in the morning.
– Information courtesy of CDOT
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