A strong winter storm impacted Southeast Arizona beginning early in the morning on December 12th and continued into the early morning hours of December 14th. This system produced heavy rainfall in the lower elevations with many valley location seeing in excess of one inch of rainfall and the mountains recording heavy snowfall.
Every event with a place to put it; 6 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS TWC wrote it up.
A strong winter storm impacted Southeast Arizona beginning early in the morning on December 12th and continued into the early morning hours of December 14th. This system produced heavy rainfall in the lower elevations with many valley location seeing in excess of one inch of rainfall and the mountains recording heavy snowfall.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Tucson, AZ wrote its last area forecast discussion before the first event at Dec 12, 9:00 AM MST, 0 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 900 AM MST MON DEC 12 2011 .SYNOPSIS...A STRONG PACIFIC STORM SYSTEM WILL BRING VALLEY RAIN AND SIGNIFICANT MOUNTAIN SNOW TO SOUTHEAST ARIZONA STARTING TODAY AND CONTINUING INTO EARLY WEDNESDAY. A DRYING TREND WILL OCCUR WEDNESDAY AND THURSDAY THEN A SLIGHT CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW RETURNS FRIDAY INTO SATURDAY. BELOW NORMAL DAYTIME TEMPERATURES WILL OCCUR THIS WEEK AND NEXT WEEKEND. && .DISCUSSION...UPPER LOW NEAR SAN FRANSISCO IS MAKING ITS WAY SOUTH ALONG THE WEST COAST. MOISTURE PLUME IS OUT IN FRONT OF THE LOW FROM THE BAJA SPUR NORTHEAST THROUGH SOUTHERN ARIZONA INTO THE MOGOLLON RIM. ATMOSPHERE IN THE PROCESS OF MOISTENING FROM THE TOP DOWN...AS OF 9 AM VERY LITTLE PRECIP HAS MADE IT TO THE SURFACE FOR VALLEY LOCATIONS. HOWEVER...SNOW HAS BEGUN FOR MOUNTAIN LOCATIONS ABOVE 6500 FEET. MOST VALLEY LOCATIONS WILL BEGIN TO SEE RAINFALL REACHING THE SURFACE BY 10 AM. A BRIEF BREAK IN THE PRECIP IS LIKELY TO OCCUR OVER CENTRAL PORTIONS OF THE CWA INCLUDING TUCSON BETWEEN 2 PM AND 9 PM IN A DRY SLOT BETWEEN MOISTURE PLUMES. UPPER LOW WILL DROP SOUTH TO JUST WEST OF SAN DIEGO BY TUESDAY MORNING A VERY MOIST FLOW WILL CONTINUE AHEAD OF THE LOW WITH SIGNIFICANT PRECIP...ESPECIALLY FOR MOUNTAIN LOCATIONS AND A WINTER STORM WARNING IS IN EFFECT THROUGH 5 PM WEDNESDAY ABOVE 6500 FEET. THE LOW WILL THEN SWING THROUGH SOUTHERN ARIZONA TUESDAY NIGHT AND FINALLY MOVE EAST OF THE AREA WEDNESDAY AFTERNOON. TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH THE WEEK WITH CLOUDS...PRECIP AND LOWER HEIGHTS. && .AVIATION...STRONG UPPER LOW LEVEL PRESSURE SYSTEM OFF SOUTHERN CALIFORNIA COAST WILL BRING MOIST SOUTHWEST FLOW OVER SOUTHEAST ARIZONA THROUGH TUESDAY MORNING. BKN-OVC CLOUDS ABOVE 12K FT AGL WITH CLOUD BASES LOWERING TO 6-12K FT AGL. CLOUD DECKS LOWERING TO 3-6K FT AGL BY 00Z TUESDAY. ISOLD-SCT -SHRA 16Z-18Z THEN SCT-NUMEROUS -SHRA AND HIGHER TERRAIN SHSN THIS AFTERNOON. AREAS OF MVFR CIGS/VSBYS DEVELOPING THIS AFTERNOON. SURFACE WIND SELY/SLY 10-20 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...NO FIRE WEATHER CONCERNS AT THIS TIME. && .HYDROLOGY...CURRENT FORECASTS INDICATES THAT THE HIGHEST RAINFALL TOTAL OVER THE NEXT 2 DAYS WILL BE EAST OF TUCSON AND OVER SOUTHWEST NEW MEXICO WITH STORM TOTAL VALUES IN THE 1-2' RANGE. THUS WILL SEE AN INCREASE IN THE FLOW IN THE RIVERS...ESPECIALLY IN THE SAN PEDRO...SAN FRANCISCO AND GILA RIVERS. LATEST FORECAST FROM COLORADO RIVER FORECAST CENTER HAS 2-3 FOOT RISES BY WEDNESDAY MORNING. && .TWC WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 12 NOON TODAY THROUGH 5 AM WEDNESDAY MORNING FOR AZZ510>512-514 ABOVE 6500 FEET. WEATHER.GOV/TUCSON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TUCSON AZ 348 AM MST MON DEC 12 2011 AZZ510>514-131100- WHITE MOUNTAINS OF GRAHAM AND GREENLEE COUNTIES- GALIURO AND PINALENO MOUNTAINS-CHIRICAHUA MOUNTAINS- DRAGOON AND MULE AND HUACHUCA AND SANTA RITA MOUNTAINS- CATALINA AND RINCON MOUNTAINS- 348 AM MST MON DEC 12 2011 ...WINTER STORM WARNING IN EFFECT FROM NOON TODAY TO 5 AM MST WEDNESDAY ABOVE 6500 FEET... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA. .DAY ONE...TODAY AND TONIGHT A STRONG PACIFIC STORM SYSTEM WILL BRING SIGNIFICANT MOUNTAIN SNOW TO SOUTHEAST ARIZONA STARTING TODAY AND CONTINUING INTO EARLY WEDNESDAY. A WINTER STORM WARNING IS IN EFFECT FROM NOON TODAY TO 5 AM MST WEDNESDAY ABOVE 6500 FEET. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THE STORM SYSTEM WILL CONTINUE TO AFFECT SOUTHEAST ARIZONA WEDNESDAY. SIGNIFICANT SNOW ACCUMULATIONS ACROSS THE HIGHER TERRAIN WILL LEAD TO HAZARDOUS TRAVEL CONDITIONS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. AZZ501>509-515-131100- WESTERN PIMA COUNTY-TOHONO O'ODHAM NATION- UPPER SANTA CRUZ RIVER VALLEY/ALTAR VALLEY-TUCSON METRO AREA- SOUTH CENTRAL PINAL COUNTY-SOUTHEAST PINAL COUNTY- UPPER SAN PEDRO RIVER VALLEY- EASTERN COCHISE COUNTY BELOW 5000 FEET-UPPER GILA RIVER VALLEY- BABOQUIVARI MOUNTAINS- 348 AM MST MON DEC 12 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA. .DAY ONE...TODAY AND TONIGHT A STRONG PACIFIC STORM SYSTEM WILL BRING VALLEY RAIN AND SIGNIFICANT MOUNTAIN SNOW TO SOUTHEAST ARIZONA STARTING TODAY AND CONTINUING INTO EARLY WEDNESDAY. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THE STORM SYSTEM WILL CONTINUE TO AFFECT SOUTHEAST ARIZONA WEDNESDAY. LOCALIZED HEAVY RAINFALL AMOUNTS MAY OCCUR AND LEAD TO HAZARDOUS TRAVEL CONDITIONS. AREAS OF HEAVY RAINFALL MAY RESULT IN AN INCREASE IN THE FLOW IN WASHES...CREEKS...AND RIVERS...ESPECIALLY THE SAN PEDRO...SAN FRANCISCO AND GILA RIVERS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. WEATHER.GOV/TUCSON
The national radar mosaic for the moment the first event began.
6 heavy snow. Local standard time, as filed.
About 20 inches of snow occurred at Hannagan Meadow.
Mt. Lemmon had about 24 to 30 inches of snowfall.
Mt. Graham had between 32 and 36 inches of snow.
The higher elevations of the Santa Rita and Huachuca Mountains had 20 to 30 inches of snowfall.
The higher elevations of the Chiricahua Mountains had 10 to 20 inches of snow.
Kitt Peak had between 10 and 12 inches of snowfall.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2011Every state in 2011This day in weather historyWarnings in Arizona, December 2011
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 2026-09-24. Each event’s entry at NCEI: 351567, 351570, 351568, 351571, 351569, 351572.