Treasure Valley commuters are dealing with snow and slippery roads Monday thanks to a warm front moving through the area.

Snow began falling in Boise shortly after 8 a.m. The National Weather Service measured 2.1 inches of snowfall at the Boise Airport by 4:15 p.m., which is more than was expected.

The snow stopped about 5 p.m., but law enforcement officials reported a slippery commute home from work and school and and warned drivers to be extra careful.

Ada County sheriff's officials reported four injury crashes between noon and 8 p.m., as well as 26 crashes where no one was injured. There were 17 slideoffs.

Idaho State Police investigated over a dozen slide-offs and other weather-related crashes on Interstate 84 all through the Treasure Valley as of between 8 a.m. and 4 p.m. ISP officials say the 42 mile portion of I-84 west of Caldwell to east of Boise is covered with snow and ice and drivers should slow down.

The estimated high temperature in Boise Monday is 33 degrees, and it shouldn't get much colder than that overnight, which will be a nice change from the teens and single digit temps during the mornings of last week. (The low temperature in Boise Monday morning was 12 degrees, according to National Weather Service reports).

The Boise School District has cancelled all evening school classes at Frank Church High School Monday night. That program, which is for students over the age of 16 who are working on their GED, attracts students from all over the Treasure Valley and officials felt it was safer for those students to stay home tonight instead of driving long distances on slippery roads.

Bogus Basin Mountain Resort expects to get 3 to 5 inches of snow Monday and possibly more overnight, which is good news for winter recreationists. As of 4 p.m., the resort had about 3 inches of new snow.

The storm system coming out of northwest won't be enough to push out polluted air hanging over the Valley for more than a week due to an inversion, when cold air is trapped near the ground.

Temperatures will warm up to the 40s on Tuesday and Wednesday, but another system from the northwest will knock temperatures to the 20s and teens on Thursday and Friday. And it's going to stay cold — below freezing — into the following week, said meteorologist Valerie Mills.

The good news is that the late-week storm, which isn't expected to bring snow, will be packing winds to disperse the stagnant air over the Valley. Despite the haze, air quality monitors in Boise and Nampa showed the air quality was still "healthy" category.