Built to Thaw: Why Ice Roads Get the Green Light

Ice roads that traverse lakes or run through municipalities generally have lighter traffic, both in terms of the weight of items moving across the ice as well as the number of users, so the roads don’t need to be built up as much as those constructed for industrial use, Head says.

The oil and gas industry and other entities performing exploration or drilling work require thicker, more well-maintained ice roads specifically because the work they do requires larger, heavier equipment.

“If you’re drilling, whether it’s for a mining or exploration project, it’s pretty deep; the deeper you go, the bigger the rig you have to have,” Miller says. “The bigger rig has more weight and requires more to transport it; you’re not going to get out to where traditionally our oil and gas is unless you have an ice road.”

Construction and Maintenance

Ice road construction requires a minimum snow depth of 6 inches, with the top 12 inches of tundra frozen to at least 23 F°— with an optimal ambient temperature of -20 F°, says Jeff Osborne, project lead for ice roads at ConocoPhillips. This typically occurs sometime in November, with construction planned for December through February.

Prep work for ice road construction, however, begins several months before the required conditions set in. In October or November crews monitor snowfall to determine when it reaches the appropriate depth and then share that information with the DNR, Osborne says.

Pre-packing the snow as it accumulates is an important prep-step prior to beginning work.

“The main reason for pre-packing the snow is one, you’re creating a base, and two, you’re decreasing the insulation value of the snow, so heat from the ground can be released more readily,” Head explains. “Whereas if you have light, fluffy snow on top of the tundra, that insulates the ground, and it takes longer to freeze.”

Depending on the ice road’s location, pre-planning can sometimes begin an entire season or more before construction is scheduled to take place.

“When we have a stream crossing, we’ll go out there in summer,” Osborne says. “It’s usually a couple of summers of efforts. We’ll survey, we’ll get the symbiosis of the stream, we’ll survey the flood banks, making sure we understand all the details and the natural flow of that stream. Then when we come in the wintertime, we’ll build up the ice once the natural ice starts to grow.”

Roads are built in segments, with crews and equipment placed strategically at different points along the path, Osborne says. With potential weather delays factored in, he estimates it takes three days to build one mile of road.

A good portion of that work involves smoothing irregularities in the tundra and creating a level surface. Crews use snow and ice chips to fill uneven spots and create a level building surface.

“Ice roads are constructed as fill; we don’t cut the tundra anywhere,” Osborne says. “We only take snow and ice chips from grounded areas, so only after the lake has frozen down to the mud line, typically around the circumference of the lake.”

Once filled, crews water the snow- and ice-packed corridor, letting it freeze in between applications until it reaches a minimum thickness of six inches. The road’s width varies depending on its intended use.

“Ice roads are 35 feet wide typically, but we’ll build them wider for certain applications,” Osborne says. “A gravel haul we might build a little wider, so the large gravel haul trucks have enough space to pass. A pipeline corridor might be a little wider, sometimes as much as 65 or 70 feet on one side of the pipeline. It just depends on the application.”

Watering generally continues through April to maintain the road’s thickness and to repair other deteriorations that occur through normal wear and tear, particularly effects from the sun as the season progresses, Miller says. Any accumulation of snow also must be removed from the roads.

“There’s more maintenance required as you get later in the season from the effects that you can feel from the sun,” Miller explains. “But if you have a big windstorm, you can’t have that snow piled up on the road. It’s like driving up here through Turnagain Arm; it’s a lot of the same equipment—snowplows and rollers.”

Although the materials and building conditions needed to build an ice road are unique, the equipment is more or less the same as that used to build asphalt or gravel roads, albeit with some modifications to suit the terrain.

“It’s similar equipment to gravel road construction—loaders, graders, those are the typical equipment that you see in a gravel road installation,” Osborne says. “We have a couple of specific trucks that we found work well on the North Slope. Articulated dump trucks, then [what] we refer to as 150-barrel water trucks, water tanks that are putting water down as well. And then additionally we utilize modified asphalt trimmers and reclaimers that we specially set up to trim the ice off lakes.”

Environmentally Sound

Constructing ice roads to reach Alaska’s otherwise inaccessible locations serves multiple purposes. The primary, and most important, is to provide a means of transporting large equipment and other materials that would be too expensive, or too unsafe, to move by other methods.

But there are other benefits as well, chief among them is good environmental stewardship.

“It costs a lot more, probably over the life of the field, but the environmental benefits are great, and we’re committed to that,” says Natalie Lowman, communications director for ConocoPhillips Alaska.

While that commitment is more widespread now, it’s a different perspective than even just a quarter-century ago.

“Today, environmental stipulations and best practices have changed,” Osborne says. “Globally, there’s a significantly greater perception by people everywhere that we’ve got to take care of the earth. But I think in the beginning, if you go back twenty-plus years, some of this was born between stakeholders, agencies, residents, local entities, and the [oil and gas] companies… working together to find solutions to protect the environment but yet provide safe access to resources and development.”

Working closely with the DNR and the Alaska Department of Fish and Game, crews closely monitor the volume of water removed from lakes to eliminate potential damage to the animal habitat and to make sure the lake is replenished during spring break-up, Osborne says.

Crews are also required to maintain constant communication with the DNR and share information they collect during the pre-planning stages.

“The companies need to come to us for each new step in the ice road construction process,” Head explains. “They have to tell us what vehicles they’re using and how many trips they’ll make, and we might suggest different vehicles to use. We ask them to take snow data for us so that we have a better idea of what the snow conditions look like in a given area.”

To further decrease the potential for adverse environmental effects, ice roads must be built in different locations every season (with a very few exceptions). Any damage sustained is typically minimal and quickly disappears.

“The vast majority of ice roads are constructed well and don’t cause unacceptable levels of tundra damage for longer than a year,” Head says. “Typically [any damage] goes away after a couple of years.”

This pervasive commitment to protecting the environment is a point of pride for Alaska’s construction crews.

“It’s a good feeling that we’re doing the right thing with the environment and yet still helping to find resources and bring them to the market,” Osborne says.