Heavy Snow — E Pima, Arizona

2002-01-30 to 2002-01-31 · E Pima, Arizona

Event narrative

Tucson International Airport received .6 inches of snow, which was the first measurable snow reported in ll years. It snowed periodically throughout the day of the 30th. Between 7:00 and 9:00 pm on the 30th, there were reports of thunder snow. Other snowfall amounts across the Tucson area were scattered. The An observer in the Rincon Mountains (4200 feet), reported 2 inches of snow on the morning of the 30th. An observer in the Tucson Mountains, reported 1 inch of snow on the morning of the 30th. On the campus at the University of Arizona, only a trace of snow was reported. Mission Manor Park received .5 inches, Palisades received 7 inches, and Mt Lemmon received 8 to 12 inches of snow. On the morning of the 31st, a combination of black frost and ice forced closures of at least 9 bridges in the Tucson metro area. Heavily traveled roads were also closed which included Oracle, 22nd, Swan, and Kino Parkway.

Wider weather episode

This storm system that brought snow to the valley floor originated over the Gulf of Alaska. By the 29th, the low pressure system dropped down over southern California and broke into two pieces. The cold core passed over norther Arizona, while the primary low passed over the Arizona-Sonora border. On the 30th, the 1000-500 mb thicknesses dropped to 5250 m and the 700 mb temperatures dropped to -15 degrees Celsius. In the mountains above 4000 feet, accumulations were heavier especially on the south facing slopes due 700 mb winds of 30 to 40 knots. More significant accumulations were unrealized at the valley floor due to freezing levels at 5000 feet and wetbulb zero at 4000 feet.

Source: NOAA Storm Events Database, event_id 5276753. Narrative written by the NWS forecast office that issued the report.