Flash Flood in Arizona, August 13, 2001

Name: Flash Flood in Arizona, August 13, 2001
Start: 2001-08-13T18:45
End: 2001-08-13T20:00
Location: Arizona

August 13, 2001 · NWS TWC · 1 event in 1 county or zone

Flooding was reported on Highway 86 east of Why by the Tohono O'hodom law enforcement.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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: 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.

Flooding was reported on Highway 86 east of Why by the Tohono O'hodom law enforcement.

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 Aug 13, 2:40 PM MST, 4 hours 5 minutes earlier.

Area forecast discussion, Aug 13, 2:40 PM MST, 4 hours 5 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
240 PM MST MON AUG 13 2001

.SYNOPSIS...A LOW PRESSURE SYSTEM OVER CHIHUAHUA WILL MOVE NORTHWEST
INTO ARIZONA TONIGHT. THIS FEATURE IS BEING STEERED BY AN AREA OF
HIGH PRESSURE CENTERED NEAR THE FOUR CORNERS REGION. THIS HIGH WILL
REMAIN SOMEWHAT STATIONARY THE NEXT SEVERAL DAYS...KEEPING
CONSIDERABLE MOISTURE OVER THE REGION.

.DISCUSSION...THE LACK OF MOISTURE WILL DEFINITELY NOT BE A MISSING
INGREDIENT FOR SHOWERS AND THUNDERSTORMS TODAY. LATEST SURFACE
OBSERVATIONS WERE SHOWING DEWPOINTS IN THE 60S TO AROUND 70 ACROSS
THE REGION...AND SATELLITE ESTIMATED PWATER VALUES WERE AROUND 1.75
FROM TUS WEST AND NEAR 1.25 TO THE EAST. DETAILS IN THE UPPER FLOW
PATTERN WERE RATHER COMPLICATED WITH ARIZONA IN BETWEEN TWO AREAS OF
HIGH PRESSURE...ONE OVER THE EASTERN PACIFIC AND THE OTHER OVER NEW
MEXICO INTO TEXAS. THE INVERTED TROUGH THAT MOVED INTO THE STATE
SATURDAY WAS CAUGHT IN BETWEEN THESE TWO CIRCULATIONS OVER WESTERN
ARIZONA. LATEST MODELS SHIFT THIS TROUGH A LITTLE EAST TODAY WITH
THE TAIL END OF IT PROVIDING SOME WEAK LARGE SCALE LIFT OVER
SOUTHEAST ARIZONA THIS EVENING. THE OTHER FEATURE TO WATCH FOR WAS
A WAVE OVER NORTHERN MEXICO AND APPEARS TO BE MAKING A NORTHWESTERLY
TRACK TOWARD SOUTHEAST ARIZONA AND SOUTHWEST NEW MEXICO. LATEST
MODELS PICK UP ON THIS FEATURE AT LEVELS ABOVE THE STANDARD 500MB
LEVEL AND MOVE IT INTO OUR CWA BY TUESDAY MORNING. SOUTHEASTERN
ARIZONA SHOULD SEE SOME INFLUENCE FROM THIS WAVE AS EARLY AS THIS
EVENING. THE ONLY LACKING INGREDIENT FOR STRONG THUNDERSTORMS WILL
BE THE INSTABILITY. CURRENT AIRMASS APPEARS TO BE TOO WARM ALOFT...
RESULTING IN WEAK CAPE ESPECIALLY FROM TUS WEST. HOWEVER...RECENT
SATELLITE IMAGERY WAS SHOWING A SIGNIFICANT THINNING OF THE DEBRIS
CLOUDINESS OVER SOUTHEAST ARIZONA. THUS...CURRENT THINKING IS THAT
WE SHOULD SEE ENOUGH DAYTIME HEATING COUPLED WITH OROGRAPHIC AND
LARGE SCALE FORCING TO PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING. LOCALLY HEAVY RAINFALL WILL BE THE MAIN
THREAT TODAY...BUT STRONG WINDS FROM WET DOWNBURST ARE NOT OUT OF
THE QUESTION TOO. BEYOND TODAY...NOT ENOUGH CHANGE IN THE MOISTURE
TO WARRANT ANY TREND IN THUNDERSTORM ACTIVITY. THUS...STANDARD
SUMMER SEASON FORECAST LOOKS ON TRACK.

.TWC...NONE.

In the hours before

Local storm report, Aug 13, 4:40 PM MST, 2 hours 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON ARIZONA
0440 PM MST MON AUG 13 2001

TIME (MST) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0330 PM    TUCSON                    AZ   FLASH FLOOD
08/13/01   PIMA                           FLOODING IN SOUTHWEST TUCSON

0335 PM    THREE POINTS              AZ   FLASH FLOOD
08/13/01   PIMA                           FLOODING IN THREE POINTS

0335 PM    MARANA                    AZ   FLASH FLOOD
08/13/01   PIMA                           FLOODING IN AVRA VALLEY AREA

0330 PM    MARANA                    AZ   WIND DAMAGE
08/13/01   PIMA                           65 FOOT HAM RADIO TOWER DOWNED

The radar

The Tucson radar (KEMX), 112 km away, was scanning. The volume nearest the first event began at 01:45 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Pima

When: August 13, 6:45 PM MST to 8:00 PM MST
Where: Pima County, 5 mi E of Why
Reported by: LAW ENFORCEMENT
Coordinates: 32.097, -111.790 (the zone’s center; the record gives no point)

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.

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

The same day elsewhere

Every storm in Arizona in 2001 Every state in 2001 This day in weather history Warnings in Arizona, August 2001

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: 5259916.