Portland may get a rare third chance this winter to hone its snow response, and transportation officials say new procedures -- and tons of salt -- will help make this one swifter.

If another winter storm materializes as forecast Thursday afternoon, the city will expand its test use of road salt and expand plow routes to include more neighborhood streets, including key routes for school buses.

Commissioner Dan Saltzman, who oversees the transportation bureau, said the city purchased 100 tons of rock salt for $20,000.

That might sound like a lot, but officials said it's only enough to treat three roads in the city: hilly stretches of Southwest Broadway, Southwest Terwilliger Boulevard and North Going Street. They'll be treated early in the storm to help prevent a repeat the sheets of ice seen earlier in the season, the officials said.

City crews will add 340 lane miles to their plow routes; that's a 30 percent increase over the 1,120 lane miles they typically clear.

Nonetheless, officials urged Portlanders to avoid travel or take transit, particularly if snow is followed by freezing rain.

The transportation agency also will request $1.2 million for snow-clearing equipment, including a grader that can clear hard-packed snow, more plow grades and equipment for sanding and salting roads. It's also asking for $1.6 million a year to beef up PBOT's weather-response staff and materials.

Those resources wouldn't be available in time for the coming storm.

The transportation bureau also will negotiate a cooperative agreement with Seattle, which sent crews to Portland to help clean up from the last storm, and it will consider paying private contractors to assist in clearing snow.

Portland's first snowstorm of the year came in the middle of a workday, prompting thousands to head home early. The exodus clogged roads for hours; some drivers ditched their cars, leaving them littered in traffic lanes.

That left residents cautious ahead of the second storm, and many stayed home. The snow was left on the roads to ice over, and freezing conditions meant it didn't melt for days.

"Portlanders are frustrated, and rightly so," Saltzman said.

The city started using road salt during the last storm, courtesy of the Seattle road crews sent in to help. The transportation bureau said it was no more effective than their preferred deicer, magnesium chloride, but that it would continue testing.

Transportation bureau Director Leah Treat acknowledged Wednesday that the timing of the application, after the roads had frozen, was likely part of the reason it was ineffective.

The state has been using salt near the California border since 2012. It's now using salt in limited applications in the Portland metro area, though it still relies heavily on magnesium chloride before and during storms.

The state transportation department, however, says its tests have shown that salt reduces crashes and results in fewer road closures and chain restrictions. It presented those findings to a panel of lawmakers on Wednesday.

On a section of Interstate 5 where the department has used salt, highway division administrator Paul Mather said, it has over a four-year period reduced the number of average annual winter-weather crashes from 115 to 45; freeway closures from 36 to 3; and tire-chain orders from 48 to 11.

Mather said those averages would rise, however, once numbers from this severe winter are included.

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus