By noon, the National Weather Service reported 1.6 inches of new snow at the Boise Airport, with more continuing to fall.
NWS earlier issued a winter weather advisory for Friday morning through 11 a.m. Saturday.
“There will be two to four inches of snow in the (Treasure Valley) and even more in the Magic Valley” around Twin Falls, NWS meteorologist Joel Tannenholz said earlier.
The forecast calls for the storm to continue through Saturday morning, he said. Flurries are expected Saturday afternoon, Tannenholz said.
The Idaho State Police reported a number of crashes on Interstate 84 and asked motorists to slow down.
By noon, roads leading away from Boise — I-84 near Fruitland and Mountain Home, Idaho 55 at Horseshoe Bend Hill and U.S. 95 at Ion Summit south of Homedale — all reported snow on the road and slick conditions.
Farther east, I-84 at Twin Falls and Pocatello and U.S. 93 south of Hollister, toward Jackpot, Nev., still had bare pavement. The storm was expected to hit those areas Friday afternoon.
In Oregon, I-84 between Baker City and La Grande was closed late Friday morning due to zero visibility at Ladd Canyon.
Field maintenance crews at the Boise Airport were ready for the storm and are working to remove snow to keep runways open and safe.
The airport does not expect to have any operational issues, spokesman Sean Briggs said.
“That being said, flights can still be delayed due to various factors, including de-icing, late arrivals, etc.,” Briggs said. “We encourage travelers to arrive 90 minutes in advance and to check in with their airlines for the latest flight information.”
The U.S. Postal Service asked residents to keep sidewalks, steps and mailboxes free of snow and ice.
“Snow and ice make delivery dangerous and slow. Maintaining a clear path to the mail box — including steps, porches, walkways and street approach — will help postal carriers maintain consistent delivery service,” Boise Postmaster Dan Corral said in a written release.
Delivery service may be delayed or curtailed whenever streets or walkways present hazardous conditions for postal carriers or when snow is plowed against mailboxes. Service is attempted again the next delivery day.
Christmas Day will be mostly cloudy and cold, with an overnight low of 19 degrees and a high of 26 degrees.
A white Christmas hits the Treasure Valley about once every four years — though recently, we’ve had one in both 2014 and 2015. This year, Santa’s sleigh will likely leave telltale track marks on rooftops throughout the valley.
After patchy fog Sunday night and Monday morning, the sun is expected to come out later Monday. By Tuesday, there will be a 40 percent chance of snow and a high near 30 degrees.
The forecast calls for dry conditions Wednesday night through next Saturday.