Flagstaff, AZ – SNOW! As cold air and Pacific moisture sweep across the Southwest, meteorologists are urging drivers to understand the difference between a Winter Storm Advisory and a Winter Storm Warning — especially along I-40 through northern Arizona and New Mexico, and I-15 north of Las Vegas.
According to the National Weather Service (NWS), a Winter Storm Warning is issued when heavy snow, sleet, or ice is expected or already occurring. In the Southwest, that typically means at least four inches of snow in 12 hours or a glaze of freezing rain that makes travel treacherous on mountain routes.
A Winter Weather Advisory signals that lighter snow or ice is expected but may still affect roads. The NWS says even minor accumulations can create dangerous conditions in the high desert, where drivers are less accustomed to snow and many vehicles lack winter tires.
Thresholds vary across the region. A system that brings advisory-level snow to Albuquerque might trigger a full warning in Flagstaff or the higher elevations outside Kingman. Rapid temperature drops and gusty winds can also lead to black ice, particularly at night.
Forecasters recommend checking weather.gov for live alerts, delaying travel during warnings, and keeping warm clothing and water in vehicles when crossing desert highways.
