Local crews with the Oregon Department of Transportation are ready to salt highways as more snow moves in to cover over the area.
The National Weather Service warned a winter storm is expected to hit Eastern Oregon this weekend, with snowfall beginning Friday afternoon and continuing into Sunday. Between 4-8 inches of snow will fall in portions of the Blue Mountains, with 3-6 inches across the Columbia Basin.
Snowfall and windy conditions with gusts of up to 35 mph are expected to create hazardous travel conditions through the weekend, with sub-freezing temperatures through the week.
Tom Strandberg, spokesperson with ODOT in Eastern Oregon, said as the chance for snow increases, motorists should keep an eye out for plows scattering salt on Interstate 84.
"Right now, salt is a useful tool for us,” he said.
The state road department ran a pilot project from 2012-17 on sections of Interstate 5 and Highway 95 to test the effectiveness of salt on roads. Strandberg said that fine tuning led the department to use about 200 pounds of salt per mile per lane, about enough to fill a large dog food bag.
Crews put down the salt in anticipation of winter storms. Salt needs to mix with moisture to activate, Strandberg explained, so applying it on wet roads just before freezing temperatures is ideal. Out here, he said, that means salting Interstate 84 and sometimes secondary roads, such as Highway 11. Crews typically apply salt on curvy or shady sections of road, but they will drop it for miles if need be.
Strandberg said motorists could think it strange to see state plows going all of 30 mph down the center of wet pavement with blades lowered to keep vehicles from passing, but that plow is probably applying salt.
The slower speed keeps the salt from bouncing off the road, and straddling both lanes allows for an even distribution of salt with a minimal amount. Strandberg asked drivers in those situations to be patient. ODOT drivers pull over occasionally to allow everyone to pass.
Getting the salt down before temperatures are too cold is key. The salt reduces the ability of ice to bond to roads, and when the temperature is near 30, 1 pound of salt can melt 46 pounds of ice, studies show. But the colder the temperature, the less effective the salt. Around 10, the salt no longer works. Strandberg said ODOT uses chemical de-icer at lower temperatures.
Salt also cuts down on ODOT’s use of sand, and Strandberg said that’s significant.
"That means we don't have to go back out and clean up," he said. "That's a labor-intensive process, and there are environmental concerns as well."
Using salt also comes with concerns. Salt corrodes steel, which the state uses in bridges and to reinforce concrete pavements. That five-year study reported the ODOT Bridge Section recommended “all bridges exposed to rock salt receive effective deck sealing or other effective deck protective treatments.”
ODOT also recommended regular washing of vehicles, including the undercarriage, to remove salt, de-icer and road grime.
Strandberg said the department also continues to plow snow from roads, and the new TowPlow is working great. ODOT in 2017 bought five of the larger plows that clear two lanes at a time, and the eastern region received one.
The city of Hermiston uses its plow in a tiered approach to clearing streets. Main traffic routes receive priority, then the hills and the downtown commercial areas. Residential roads come third. But that depends on the weather. The city will call crews working downtown or in neighborhoods to clear off main roads.