Colorado & Denver News

by Andrea Lopez
FRISCO, Colo. (CBS4) ― If you've ever been stuck in traffic or experienced a closure while on Interstate 70, there's a chance the delays were due to Mother Nature. I-70 is one of the most environmentally-challenging corridors in the United States.

The Colorado Department of Transportation has spent more than $13 million on unanticipated natural disasters in the last five years alone.

Ken Wissel has worked for CDOT for 32 years now and said there isn't a month where he hasn't plowed snow. Twenty of those years have been spent in the mountains. He talked about the reasons why the interstate is such an environmental challenge for the crews that have to maintain it and clean up the natural disasters that often close parts of it.

"One of the first things we look at, if you look at the geographical footprint of I-70 there's three major traverses of altitude," said Wissel. "We have the first part or the west part of Denver up over Genesee and Floyd Hill and that's where you have two or three thousand feet of elevation gain right off the start. We do that again at the Continental Divide at over 11,000 feet and across Vail Pass -- again another major mountain pass to traverse."

In the wintertime, it's not uncommon to have clear weather in the Denver area and to encounter snow by the time you reach the Eisenhower Tunnel because of the elevation gains along the mountain corridor. Crews are constantly challenged to keep I-70 open. Last year, on the stretch of roadway from Vail to Golden, CDOT plowed enough miles to stretch around the world about 14 times. It used 28,705 tons of salt and sand on that same stretch, 4,626 tons of Ice-Slicer, and 667,064 gallons of liquid de-icer. It cost CDOT nearly $2 million for snow removal in that area alone. Even so, weather closed parts or all of the mountainous interstate for a total of about 80 hours last winter.

As if snow removal wasn't challenging enough, CDOT crews have had to deal with unexpected avalanches that have closed mountain passes and parts of the interstate. It works closely with the Colorado Avalanche Information Center to try and determine which areas along I-70 need to be maintained and when.

"Well of course we try to make it safe for the traveling public at all times," said Wissel. "And we have staff in the avalanche information center that work directly for us -- and in conjunction with the National Weather Service -- and our own staff and everything else to try to get a handle on the conditions in the winter time. Whenever a hazard warning comes up, we have to look at the safety of the traveling pubic first and foremost even though we know a lot of people are wanting to recreate, that interstate commerce is involved, and commuting people."

CDOT regularly maintains 16 slide paths along the mountain corridor. That means crews will blast when too much snow has built up or the snowpack is unstable, bringing it down in a controlled fashion before it comes down on its own.

"Our version of success is to make a snowslide and not let it get to be a big one where it really impacts the highway and takes a long time to clean up and that kind of thing," said Wissel. "But sometimes Mother Nature doesn't give you those cards to play with and you're dealt not as good a hand as what you're sometimes able to work with."

In 2003, extreme blizzards and a massive avalanche shut down I-70 for days. The avalanche was near Silver Plume, and the path the snow took was not a known slide path. It caught everyone by surprise, and trapped people in the mountains.

"People who were in town were pretty stressed out. It was an unfortunate situation for a lot of people who were at the end of their stay, people who were trying to come in couldn't get in -- it was a busy weekend," said Frisco business owner Dan Fallon. "There was a lot of stress in the town from travelers, residents and business owners. You deal with it as best you can. You hope it doesn't happen on a weekend during the busiest week of the year -- that's always unfortunate."

In the spring and summer times, rockslides and mudslides are common natural disasters that can affect travel on I-70. This summer, a mudslide near Eagle brought traffic to a halt for several hours and massive congestion to the small community of Wolcott as it was the only place for people to exit off of the roadway (if they could make it to the exit). As people tried to use Highway 6 as an alternate route to get around the mudslide on the interstate, they realized that it, too, was blocked and congested.

"Mostly mudslides are dictated by what Mother Nature does," said Wissel. "You have a rain event that's slow moving, dumps a lot of water in an area in short amount of time -- it's going to saturate the ground or run right off the top of it. If it runs right off the top it's going to pick up debris and rock and everything else and dump it right on the highway. If it gets under there and lubricates and makes super wet soil, it looses it's stability on the side of the hill and gravity is going to win and it's going to run."

About $3 million a year is spent on rockfall mitigation. CDOT crews blast and bring down unstable rock to try and prevent rockslides. They also put up rockfall netting in key areas -- or areas that have been identified as potentially dangerous. The strongest, tallest, and longest rockfall netting in the state stands on Georgetown Hill. CDOT spends about a $1.5 million a year on that area alone. To date, about $8 to $10 million has been spent on Georgetown Hill.

"We have a program that's been ongoing for several years to try to mitigate the problems of those areas on an ongoing basis," said Wissel. "Georgetown Hill is probably the most infamous area and it's one of the biggest challenges for us along the I-70 corridor."

Despite all of the rockfall mitigation work, unexpected rockslides have killed seven people in the last eight years.

Those are known natural disasters. Sometimes, the unimaginable happens. Last summer, a mine shaft collapsed in the median of I-70. It cost CDOT an unexpected $1.7 million and quite a few traffic headaches for travelers.

"CDOT was working on a project just west of Idaho Springs they were trying to fix something in the median of the highway -- I believe they were trying to create a crossover and in the process of trying to create a crossover from the eastbound to the westbound lanes they came up against what they originally thought was a sinkhole (that was the language that was originally used)," said Joann Sorensen, a Clear Creek County resident and former commissioner.

"Well, what they found out was that it was a mine shaft, and no matter how much concrete they were dumping down that mine shaft they weren't even able to get a solid surface to create the crossover that they wanted. Clear Creek County is through this valley, parallel to the creek where all of the mining and milling activity took place back in the early 1900s and late 1800s. Clear Creek County is honeycombed with that kind of man made feature under the surface. It took me an hour to go five miles from my home to Idaho springs to attend a meeting."

Just as spring was transitioning into summer in 2003, a massive sinkhole appeared in the westbound lanes on Vail Pass after a culvert failed, creating more closures and traffic headaches for drivers. That sinkhole costs CDOT $3.5 million to fix and an additional $3 million in culvert inspections and repairs to prevent the same thing from happening again.

"We've got culvert sinkholes where the design of the interstate, when it was built, it's old enough now that a lot of those features have reached their lifespan," said Wissel.

"In the last couple of years we've been doing some remedial type work to investigate and look at the known fact that we're getting to that point and how do we go about getting ahead of schedule instead of having the sinkhole that happened at Vail from happening again. So there's been a lot of work being put in on larger culverts 42 inches and larger, but we're finding out we've got a lot of smaller culverts that are going to need the same thing."

Colorado's trucking industry and CDOT have said that I-70 is one of the most challenging mountain corridors in the United States, and it's constantly challenging crews to keep it open for those who drive it.

Additional Resources:

• See an overview of the Project I-70 special series of reports on CBS4, with additional links and Andrea Lopez' blog about the assignment.
  

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