Flash Flooding and Flooding in Arizona, July 30 to 31, 2010

Name: Flash Flooding and Flooding in Arizona, July 30 to 31, 2010
Start: 2010-07-30T11:10
End: 2010-07-31T12:00
Location: Arizona

July 30 to 31, 2010 · NWS TWC · 5 events in 2 counties and zones

Numerous thunderstorms formed within a very moist atmosphere over southeast Arizona, producing heavy flooding rainfall at many locales. Many creeks, washes and rivers experienced heavy runoff and elevated flows.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 1
Injuries: 0
Property damage: $620,000
Crop damage: None recorded
Events: 5

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.

What forecasters said that day

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 Jul 30, 9:15 AM MST, 1 hour 55 minutes earlier.

Area forecast discussion, Jul 30, 9:15 AM MST, 1 hour 55 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
915 AM MST FRI JUL 30 2010

.SYNOPSIS...A SERIES OF WEATHER DISTURBANCES ACTING ON DEEP MOISTURE
IN PLACE OVER SOUTHEAST ARIZONA WILL CONTINUE TO PRODUCE DAILY CROPS
OF THUNDERSTORMS THROUGH THIS WEEKEND. VERY HEAVY RAIN...FLOODING
AND ISOLATED MICROBURSTS WILL BE THE MAIN THREATS.

&&

.DISCUSSION...AGREE WITH PREVIOUS DISCUSSION THAT ANOTHER DECENT
RAIN EVENT BEGINNING LATER THIS AFTERNOON AND CONTINUING INTO THE
NIGHT WOULD WARRANT A FLASH FLOOD WATCH SINCE MANY AREAS RECEIVED
GOOD RAIN AMOUNTS AND A NUMBER OF WASHES AND STREAM BEDS FLOWING
THIS MORNING. BIGGEST QUESTION IS WHETHER TO INCLUDE ENTIRE AREA OR
HONE IN ON ONE PARTICULAR SECTOR. MODELS TEND TO POINT TO EXTREME SE
PART OF SE AZ...BUT THEY HAVE NOT BEEN FAR ENOUGH N AND W WITH HVY
RAINS LAST FEW DAYS. WHILE DIVERGENCE/DEFORMATION NW OF THE SHEAR
AXIS STRETCHING FROM UPPER CIRCULATION NEAR NM BOOTHEEL SWWD OFF
BAJA SHOULD SUSTAIN CONVECTION PAST SUNSET...QUESTION REMAINS AS TO
WHETHER ATMOSPHERE CAN RECOVER OR HEAT UP ENOUGH TO GET THE 1.88
INCHES PRECIPITABLE WATER VALUES TO CONVECT VIGOROUSLY. IF
SO...THERE IS MUCH BETTER FLOW TODAY WHICH COULD HELP WITH
ORGANIZATION AND MICROBURST THREAT.  WHILE ONE WOULD THINK THIS
MOVEMENT WOULD MINIMIZE FLASH FLOODING THREAT...STORMS CAN STILL BE
PLENTY EFFICIENT HEAVY RAIN PRODUCERS AND AS MENTIONED...IT MAY NOT
TAKE TREMENDOUSLY HEAVY AMOUNTS TO CREATE FLOODING ISSUES.

&&

.AVIATION...SCT TSRA DEVELOPING AFT 19Z BECOMING MORE NUMEROUS AFT
22Z AND CONTINUING THROUGH AT LEAST 06Z. CIGS AS LOW AS 1K AGL AND
VSBYS UNDER 1 MILE WITH HEAVY RAIN ASSOCIATED WITH STRONGER STORMS.
SURFACE WINDS GENERALLY LESS THAN 12 KTS EXCEPT THUNDERSTORM OUTFLOW
GUSTS TO 45 KNOTS POSSIBLE. PATCHY IFR CIGS AND VSBYS LIKELY AGAIN
TONIGHT FROM 06Z TO 15Z. ANOTHER ACTIVE DAY OF THUNDERSTORMS IS
FORECAST SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.FIRE WEATHER...NO FIRE WEATHER CONCERNS AT THIS TIME.

&&

.PREV DISCUSSION...WIDESPREAD LOCALLY HEAVY PRECIPITATION ACROSS THE
AREA OVER THE PAST 12 HOURS WITH SEVERAL AREAS OF FLOODING CONCERNS
STILL ONGOING. UPPER LEVEL DIFFLUENCE CONTINUES IN BETWEEN IMPULSES
JUST EAST AND JUST SOUTH OF OUR AREA. EXPECT ENHANCED FLOW AS WELL
AS MOISTURE WELL ABOVE NORMAL TO RESET THE ATMOSPHERE FOR MORE
THUNDERSTORMS BY LATER TODAY AND TONIGHT. A FLASH FLOOD WATCH IS
UNDER CONSIDERATION SOMETIME AFTER 18Z TODAY...PERHAPS AFTER 21Z FOR
OUR AREA.

ELEVATED THUNDERSTORM COVERAGE AND RAINFALL INTENSITY THROUGH THE
WEEKEND. THE FIRST HALF OF THE NEW WEEK WE BEGIN TO SEE A WESTERLY
COMPONENT RETURN TO OUR FLOW FOR AT LEAST PART OF OUR AREA AS THE
HIGH WEAKENS AND SHIFTS EASTWARD A BIT. THIS WOULD ULTIMATELY LEAD
TO A DOWNTURN IN ACTIVITY BY THE SECOND HALF OF THE NEW WEEK.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

WEATHER.GOV/TUCSON

In the hours before

Local storm report, Jul 30, 7:51 AM MST, 3 hours 19 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
751 AM MST FRI JUL 30 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0850 PM     FLASH FLOOD      6 NW BISBEE             31.49N 109.96W
07/29/2010                   COCHISE            AZ   OTHER FEDERAL

            BANNING CREEK FLOODED ALONG HIGHWAY 82. SEVERAL HOMES
            TEMPORTAILY CUTOFF FROM MAIN ROAD. USGS GAGE.

1035 PM     FLASH FLOOD      12 SW MESCAL            31.87N 110.57W
07/29/2010                   PIMA               AZ   OTHER FEDERAL

            CIENEGA CREEK ROSE 8FT IN 30 MINUTES...CRESTED 4FT ABOVE
            BANKFULL. USGS GAGE SITE.

1105 PM     FLASH FLOOD      NOGALES                 31.36N 110.93W
07/29/2010                   SANTA CRUZ         AZ   MESONET

            6FT RISE ON NOGALES WASH IN 30 MINUTES ON ALERT GAGE.
            FLOODING REPORTED BY BROADCAST MEDIA DOWNSTREAM FROM
            ALERT GAGE SITE.

1205 AM     FLASH FLOOD      1 ESE TUCSON            32.23N 110.92W
07/30/2010                   PIMA               AZ   NWS EMPLOYEE

            NUMEROUS STREETS FLOODED IN MIDTOWN TUCSON.

1215 AM     FLASH FLOOD      TUCSON                  32.24N 110.94W
07/30/2010                   PIMA               AZ   BROADCAST MEDIA

            VEHICLE TRAPPED IN RISING WATER 2ND ST. AND EUCLID AVE.

1230 AM     FLASH FLOOD      4 ENE TUCSON            32.26N 110.88W
07/30/2010                   PIMA               AZ   COUNTY OFFICIAL

            ALAMO AND ARCADIA WASHES FLOODED...BLOCKING SEVERAL
            STREET CROSSINGS.

1235 AM     FLASH FLOOD      2 SSW TUCSON            32.21N 110.95W
07/30/2010                   PIMA               AZ   COUNTY OFFICIAL

            ARROYO CHICO FLOODED NEAR CHERRY ST.

&&

PYTLAK

Local storm report, Jul 30, 8:22 AM MST, 2 hours 48 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
822 AM MST FRI JUL 30 2010

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0930 PM     HEAVY RAIN       HUACHUCA CITY           31.63N 110.34W
07/29/2010  M3.05 INCH       COCHISE            AZ   TRAINED SPOTTER

            FELL BETWEEN 825 AND 930 PM.

&&

PYTLAK

The radar

The Tucson radar (KEMX), 86 km away, was scanning. The volume nearest the first event began at 18:10 UTC.

Open the radar archive at this moment

Event by event

3 flash flood, 2 flood. Local standard time, as filed.

Flash Flood, Pima

When: July 30, 11:10 AM MST to 11:30 AM MST
Where: Pima County, 1.04 mi SSW of Naviska to 1.35 mi SW of Tuscon Marana Nw Airport
Cause: Heavy Rain
Deaths: 0 direct, 1 indirect
Property damage: $20,000
Reported by: Newspaper
Coordinates: 32.467, -111.240

Heavy rain caused poor visibility and ponding of water on Interstate 10. The driver of an automobile lost control of vehicle in the rain and crashed into a semi-tractor trailer which had slowed to under 15 mph because of the rain. The driver of the automobile died at the scene. In addition, heavy rain caused a berm to breach, which flooded an equestrian center. Hay and feed used for horses at the facility was ruined.

Flash Flood, Santa Cruz

When: July 30, 4:45 PM MST to 7:00 PM MST
Where: Santa Cruz County, 2.89 mi NE of Nogales to 1.2 mi NW of Nogales
Cause: Heavy Rain
Property damage: $100,000
Reported by: Broadcast Media
Coordinates: 31.380, -110.896

Flash flooding from rainfall south of the International Border resulting in the Nogales Wash rising 7 feet in 15 minutes. This caused some damage to the bank protection including three concrete panels in the wash. Part of Old Tucson Road, which parallels the wash, was partially eroded.

Flash Flood, Pima

When: July 30, 8:00 PM MST to July 31, 1:00 AM MST
Where: Pima County, 22 mi ENE of Tucson to 7.78 mi ENE of Casas Adobes
Cause: Heavy Rain
Property damage: $500,000
Reported by: County Official
Coordinates: 32.352, -110.582

Torrential rainfall across portions of eastern Pima county resulted in numerous reports of flash flooding in the Tucson metro area. Flash flooding was observed on Tanque Verde Creek. The flow of the creek peeked at 11.69 feet at Tanque Verde Guest Ranch, resulting in the flooding of approximately 30 homes on Barbary Coast Road, Gold Dust Road, and Kitt Carson. Additionally, numerous swift water rescues were performed in the Tucson metro area, near the county fairgrounds, in the Recon Valley area, and on the Old Spanish Trail in the Hilton Head Ranch area.

Flood, Pima

When: July 31, 3:00 AM MST to 6:00 AM MST
Where: Pima County, 1.15 mi SSW of Rillito to 1.14 mi SSE of Cortaro
Cause: Heavy Rain
Reported by: Other Federal Agency
Coordinates: 32.404, -111.154

The Santa Cruz river at Cortaro Rd rose to about 3 feet above its flood stage.

Flood, Pima

When: July 31, 11:00 AM MST to 12:00 PM MST
Where: Pima County, 10 mi NW of Marana to 10 mi NE of Marana
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 32.552, -111.341

The Santa Cruz River near Trico Road was reported to be topping its banks.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Flash Flood, Pima	2010-07-30	25	Female	Vehicle/Towed Trailer	Indirect

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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

The same day elsewhere

Every storm in Arizona in 2010 Every state in 2010 This day in weather history Warnings in Arizona, July 2010

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 2026-09-24. Each event’s entry at NCEI: 243602, 238352, 238130, 238353, 238137.