The Gallatin Valley is getting hit with a hefty snow storm Thursday that has dumped more than a foot of snow in some areas so far with more expected throughout the day and into the night.

As early afternoon, 18 to 20 inches of snow had fallen in some areas. Snow continues to fall at a rate of about one inch each hour.

The National Weather Service has extended a Winter Storm Warning until midnight for Madison and Gallatin counties for the mountains and valleys.

The Montana Highway Patrol responded to several accidents across the valley Thursday morning. Two crashes were reported on Interstate 90 and several slideoffs took place on Jackrabbit Lane.

Between 4 p.m. Wednesday and 2 p.m. Thursday, Montana Highway Patrol dispatch in Gallatin County said troopers had responded to about 50 crashes.

There were no major crashes, mostly just slideoffs, according to a MHP dispatcher.

Motorists are urged to drive slowly and use extra caution because of the poor road conditions.

“People just need to take a little extra time to get where they’re going and have little patience,” Trooper Patrick McLaughlin said.

McLaughlin also warned about slushy roads becoming icy as temperatures drop. Even if roads look clear, they could have black ice on them, he said.

Road crews were out in full force plowing the roadways. On Interstate 90 late Thursday morning plows were running two at a time, one behind the other in an attempt to clear the road.

The Winter Weather Advisory for elevations below 5,000 feet has been upgraded to a Winter Storm Warning.

Temperatures are expected to dip into the teens Thursday night. It is possible the precipitation could melt somewhat and refreeze overnight, creating slick road conditions Friday morning. Morning motorists are being urged to use caution.

Additionally, expect visibilities to be reduced to less than one mile at times in areas of falling snow.

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For the latest road conditions, click here.