Editor's note: This story originally appeared in 2009

I wonder why crews never plow the roads around Boise.

BOISE - When the weather turns to snow in the Treasure Valley - the drive to work can quickly change from a simple task to a treacherous chore.

In Ada County, crews use a variety of tools - but one thing you don't often see in widespread use is snow plowing. While it isn't unheard of - it isn't the first line of defense for Ada County Highway District crews.

The Valley's climate means snow events don't often bring more than a few inches of fluffy precipitation, which leads the highway district to start with other methods.

ACHD spokesperson Robbie Johnson says her agency tries to match the method to the madness.

"Typically the kind of weather conditions that we see is that you get that small amount of snow and it gets icy, so you tend to see the anti-icing method first," she said.

That anti-icing liquid is a mix of magnesium-chloride applied by trucks on streets around the area -- often before a storm arrives. It helps keep ice from forming on the roads.

The next line of defense is sand, which is put at intersections and in many residential areas. It helps melt the snow as traffic drives over the top of the sand and snow.

So when do the plows come out of hiding?

"When things get really undrivable, they will plow," Johnson said. "Typically, we're not going to say 'let's go plow the whole county.'"

Instead, crews target certain areas - including major roads. But plowing can cause a set of new problems.

If you were to plow Fairview (for instance), you create snow banks and block driveways, Johnson said. The snow also covers storm drains which can lead to flooding.

Plowing is a two step process -- first crews have to get the white stuff off the road -- then they have to remove snow banks.

Some of the angriest calls we've ever received is when we've plowed in someone's driveway, she said.

ACHD has its own fleet of plows, and also hires contractors to come in and perform additional plowing if needed. Johnson says there is no way to scrape every bit of snow and ice off the road, so even when plows are used, sand and anti-icing liquid are also part of the mix to keep streets safe for drivers.