Arizona, 2020

Flash Flood in Arizona, February 23, 2020

February 23, 2020 · NWS PSR · 1 event in 1 county or zone

Widespread rain, moderate to heavy at times, occurred on Saturday February 22nd and the excessive rain eventually led to episodes of areal flooding across higher terrain areas to the east of Phoenix. One of the more problematic areas was the Tonto Creek basin; rainfall amounts of 3 inches or more along the basin and upstream caused areal flooding to occur and forced the closure of several low…

Where it happened

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The toll

Deaths
0
Injuries
0
Property damage
$20,000
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 PSR wrote it up.

Widespread rain, moderate to heavy at times, occurred on Saturday February 22nd and the excessive rain eventually led to episodes of areal flooding across higher terrain areas to the east of Phoenix. One of the more problematic areas was the Tonto Creek basin; rainfall amounts of 3 inches or more along the basin and upstream caused areal flooding to occur and forced the closure of several low water crossings. Rainfall diminished during the afternoon and evening on the 22nd allowing streamflow to level out somewhat but a new round of heavy showers occurred during late evening Saturday and into the early morning on the 23rd. The new round of moderate to heavy showers occurring on an already saturated ground led to a spike in stream flow and produced flash flooding near Punkin center shortly after midnight. According to broadcast media, at about 0140MST a motorist was rescued while trying to cross Tonto Creek at the store crossing in Punkin Center. An Areal Flood Warning remained in effect for the area at the time of the rescue. No injuries were reported, fortunately.

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 Phoenix, AZ wrote its last area forecast discussion before the first event at Feb 22, 11:09 PM MST, 1 hour 51 minutes earlier.

Area forecast discussion, Feb 22, 11:09 PM MST, 1 hour 51 minutes before
Area Forecast Discussion
National Weather Service Phoenix AZ
1109 PM MST Sat Feb 22 2020

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
Showers and isolated thunderstorms will linger overnight as a low
pressure system moves eastward through Arizona. In the wake of the
storm, below normal temperatures are expected Sunday along with
isolated showers across the higher terrain north and east of
Phoenix. A return to near normal temperatures is likely early next
week, followed by a warming trend later in the week as high pressure
builds across the intermountain West.

&&

.DISCUSSION...
Shower activity has continued to decrease across the forecast
area. Though there will continue to be some showers (and a few
thunderstorms) overnight, the threat for flash flooding has
diminished quite a bit. Therefore, and in coordination with WFOs
Tucson and Flagstaff, the Flash Flood Watch is cancelled for the
remainder of the evening.

Please see our Twitter feed for rainfall statistics from this
event.

&&

.PREVIOUS DISCUSSION...

The long fetch of deep moisture is clearly evident on water vapor
imagery and extends southwestward well into the tropical east
Pacific. This atmospheric river has pushed east of the Phoenix,
exposing the lower clouds lifting cyclonically towards the surface
low located near the CA/NV/AZ triple-point. Rain totals so far today
have been significant, with Sky Harbor Airport more than
doubling the previous daily precipitation record set over
100 years ago. Elsewhere, much of the Valley received between
three quarters of an inch and one inch of rain, and as much as one
to two inches was observed across the higher terrain of Maricopa and
Gila Counties.

Operational GFS continues to trend slower with regard to the
upper low as it weakens and translates eastward through northern
Arizona. Wrap-around shower activity will likely linger past
midnight as depicted by the HRRR and PoPs have been increased
accordingly. In the wake of the low pressure system Sunday, low
clouds and isolated showers will persist, particularly from Phoenix
north and eastward. Latest NBM is a bit cooler as well with high
temperatures below normal in the lower to mid 60s across central
Arizona. However, further west away from the influence of the low
pressure system, temperatures will still manage to climb into the mid
to upper 70s.

&&

AVIATION...Updated at 0555Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Some lingering effects of the upper and trailing portions of
storm system will continue to effect the TAF sites through mid to
late Sunday morning. Showers in the vicinity will mostly taper off
before sunrise. Although isolated showers remain possible between
sunrise and late morning the probabilities and confidence were
too low to include mention of them in the TAFs after 11Z. There is
also a slight chance of patchy fog early this morning but the
confidence was also too low to include mention in the TAFs. Expect
variable low cloud BKN CIGs and SCT decks from 5-8kft through
late morning to early to mid afternoon on Sunday. Winds near 5-10k
will favor the southwest to southeast before favoring the east
for several hours beginning around 11Z. However, confidence on
wind directions is currently fairly low due to the lingering
showers that are forecast to move through the area.

Southeast California/Southwest Arizona including KIPL and KBLH:

Lingering showers in the vicinity of KBLH will taper off very early
in the period. Moderate winds at KIPL around 8-13kt at KIPL will
be from the west and northwest during the period. Winds at KBLH
will be light and variable until midday when they will favor the
north and become a bit breezy with gusts near 17kt. FEW-SCT-BKN
mid level clouds should prevail through early to late Sunday
afternoon before becoming clear to mostly clear.

&&

.FIRE WEATHER...
Monday through Friday:
No significant changes to the extended outlook...Conditions will
continue to dry with minimum RH values dropping into the 10-25%
range by midweek and declining overnight recoveries. Winds will
behave more typical for the week with directions favoring
terrain/diurnal trends. Speeds will also remain fairly light
outside of occasional afternoon breezes.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 4 AM PST Sunday for CAZ562.

&&

DISCUSSION...Iniguez/Hirsch
AVIATION...Sawtelle
FIRE WEATHER...Deems

In the hours before

Local storm report, Feb 22, 7:03 PM MST, 5 hours 57 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
703 PM MST SAT FEB 22 2020

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

0103 PM     FLOOD            6 SE PUNKIN CENTER      33.79N 111.26W
02/22/2020                   GILA               AZ   LAW ENFORCEMENT

            A CROSS ROAD AT TONTO CREEK CLOSED AS
            REPORTED BY GCSO.

&&

PI
Local storm report, Feb 22, 7:04 PM MST, 5 hours 56 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
704 PM MST SAT FEB 22 2020

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

0513 PM     FLOOD            3 SE PUNKIN CENTER      33.82N 111.28W
02/22/2020                   GILA               AZ   LAW ENFORCEMENT

            BAR X ROAD CROSSING AT TONTO CREEK CLOSED AS
            REPORTED BY GCSO.

&&

PI
Local storm report, Feb 22, 7:08 PM MST, 5 hours 52 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
708 PM MST SAT FEB 22 2020

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

0336 PM     FLOOD            1 SE GLOBE              33.38N 110.77W
02/22/2020                   GILA               AZ   LAW ENFORCEMENT

            BEER TREE CROSSING AT PINAL CREEK CLOSED AS
            REPORTED BY GCSO.

&&

PI

The radar

The Phoenix radar (KIWA), 72 km away, was scanning. The volume nearest the first event began at 07:59 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Gila

When
February 23, 1:00 AM MST to 5:30 AM MST
Where
Gila County, 3.68 mi ESE of Punkin Center to 5.27 mi S of Punkin Center
Cause
Heavy Rain
Property damage
$20,000
Reported by
Broadcast Media
Coordinates
33.841, -111.266

Widespread rain across the high terrain east of Phoenix on Saturday February 22nd led to areal flooding in the Tonto Creek basin north of Lake Roosevelt. Early in the morning on February 23rd, a fresh batch of showers and weak thunderstorms occurred which produced another period of moderate to heavy rain. The additional rain fell in a short period on already saturated ground and led to a rapid rise in the streamflow on Tonto Creek and as a result flash flooding occurred. According to local broadcast media, at 0140MST a motorist needed to be rescued while trying to cross Tonto Creek at the store crossing in Punkin center. The motorist was not injured. While a flash flood warning was not in effect at the time of the rescue, an areal flood warning remained in effect for the area; the warning was issued during the middle of the day on Saturday the 22nd.

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

More

Every storm in Arizona in 2020Every state in 2020This day in weather historyWarnings in Arizona, February 2020

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: 870543.