Like phases of the moon, crashes on or around the only two North Idaho mountain passes during the winter months are predictable.

On Jan. 7, the Montana Department of Transportation announced it had to close Interstate 90 from the Idaho/Montana border (Lookout Pass) east to St. Regis due to an avalanche blocking eastbound and westbound lanes between Taft and Saltese.

On Jan. 6, Idaho State Police troopers completely shut down westbound traffic and partially shut down eastbound traffic on 4th of July Pass for several hours after a non-chained-up semi-truck lost control on the slick roads and barreled through the center jersey barriers.

ISP Cpt. John Kempf said it is a typical situation that ISP runs into on both Lookout and 4th of July every year.

“It’s such a unique portion of interstate compared to really anywhere else that we have in Idaho because there’s very little shoulder, you have a jersey barrier that runs down the middle, and then jersey barriers on both sides.”

Kempf stops just short of saying that all the blockages on the passes are caused by commercial vehicles, he said many of the major ones are due to their sheer size and amount of space they can take up.

According to Megan Jahns, Idaho Transportation Department spokeswoman, her department has recorded 106 total crashes between Wolf Lodge to Rose Lake from November thru February in the last five years Commercial vehicles account for roughly 19% of the average annual daily traffic on this particular pass, but 24% of the 4th of July Pass crashes involve them.

“Most crashes (commercial and otherwise) don’t block lanes, but 26% do,” Jahns said. “For commercial crashes, it becomes more likely that lanes will be blocked and 44% over the last five years did block lanes.”

On Lookout Pass, the statistics show a similar pattern.

ITD recorded 101 total crashes from milepost 64 to the Idaho/Montana state line from October through March in the last five years, 47% of which involved commercial vehicles - though they only account for roughly one-third of the traffic on that stretch.

With commercial vehicles accounting for many of the major pass backups and shutdowns, Kempf stressed the effort troopers put into enforcing chain-up laws. While he added that most commercial vehicles follow the rules, it only takes one to ruin it for everyone else.

As far as standard passenger vehicles, ISP sees more eastbound crashes due to many drivers coming from areas that don’t prepare them for winter travel in either equipment or experience.

“I have been out there and I have had people say to me ‘I have never driven in this, I'm scared, and I’m just going to stay here,” Kempf said. “Then we tell them, ‘well, you can’t stay here, we need to plow,’ and so, as crazy as it sounds, we have people that pay a tow truck to tow them up and over the passes. It happens about every snowstorm.”

When it comes to limiting the number of crashes on the passes, Kempf stressed the basics- be prepared, slow down, and stay home if conditions are too hazardous.