The National Oceanic and Atmospheric Administration is forecasting a cooler than average winter in the Northwest.

Despite this ominous forecast, driving on Interstate 84 may be safer than in recent winters because of an addition to the Oregon Department of Transportation’s arsenal against winter’s icy grip — rock salt.

Rock salt will be used to combat ice on Interstate 84 this fall and winter for the first time in at least two decades.

“This could really make a difference,” said Ace Clark, ODOT’s District 13 manager. “We could reduce crashes and road closures.”

The salt will be used along with the liquid magnesium chloride and crushed gravel ODOT has been using for years to make winter roads safer.

“(The rock salt) will be another tool in our toolkit,” said Tom Strandberg, Oregon Department of Transportation’s Region 5 public information officer.

Salting roads prevents ice building by altering the freezing point of water, Strandberg said. Water with a higher salt content has a lower freezing point than water with less salinity, which leads to melting and preventing falling snow or rain from freezing.

The magnesium chloride ODOT has long used also lowers the freezing level of water, but not to the degree that salt does, Strandberg said.

Rock salt will be applied on I-84 and a short portion of Interstate 82 this fall and winter as part of Phase II of an ODOT pilot project being conducted to determine how effective salt is at preventing accidents. Phase II of ODOT’s pilot project calls for rock salt to be used on I-84 from the Idaho border to Boardman and on Interstate 82 for about 10 miles from Umatilla southwest to I-84. The plan also allows ODOT to use rock salt in limited quantities on I-84 from Boardman to Portland when there are exceptional circumstances.

The rock salt may have a significant impact on safety if the results of Phase I of ODOT’s pilot project are any indication. During the first phase, ODOT used salt for the past five years from November through March on two roadways: a 120-mile stretch of U.S. Highway 95 in the southeastern corner of Oregon from the Nevada to Idaho border, and an 11-mile stretch of Interstate 5 over Siskiyou Pass at the south end of the state. The number of crashes on the I-5 test area dropped by 27 percent, and by 23 percent along the salted portion of Highway 95, according to ODOT statistics published in a pamphlet titled “ODOT’s use of solid salt.”

These numbers are “very encouraging, for sure,” Clark said.

See complete story in Friday's Observer