Heavy Snow in Arizona, January 30 to 31, 2002

Name: Heavy Snow in Arizona, January 30 to 31, 2002
Start: 2002-01-30T05:50
End: 2002-01-31T08:00
Location: Arizona

January 30 to 31, 2002 · NWS TWC · 1 event in 1 county or zone

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 toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS TWC wrote it up.

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.

Event by event

1 heavy snow. Local standard time, as filed.

Heavy Snow, E Pima

When: January 30, 5:50 AM MST to January 31, 8:00 AM MST
Where: E Pima forecast zone
Reported by: OFFICIAL NWS OBS.

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.

What these are

Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Arizona in 2002 Every state in 2002 This day in weather history Warnings in Arizona, January 2002

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 5276753.