(CNN)It's mid-May; spring has sprung. It's also snowing in the Pacific Northwest.
A late spring snowstorm is bringing snow across upper elevations in the Western United States. Winter storm warnings are even posted in Northeastern Washington.
Elevations above 4,500 feet are expecting 6 to 12 inches on Tuesday.
Interstate-90 near Washington's Snoqualmie Pass saw conditions deteriorate to the point a traction tire advisory was issued.
As the storm moves farther East, cities in the Rocky Mountains could see significant snow accumulation. Higher elevations in the Rockies could see over a foot of snow.
Idaho and Western Montana will see snow on Tuesday evening. Wyoming, Utah and Colorado are expected to have snow into Thursday.